PSD12: The 12th International Conference on Position Sensitive Detectors

12 Sept 2021, 16:00 → 17 Sept 2021, 13:40 Europe/London

Teaching and Learning Building (University of Birmingham)

Louise Walczak (University of Birmingham), Nigel Watson (University of Birmingham (GB)), Philip Patrick Allport (University of Birmingham (UK)), Tony Price (University of Birmingham (GB))

Latest news:

New conference dates:

PSD12 will now take place from Sunday 12 - Friday 17 September 2021.

---

Overview:

In person registration is now closed due to the needs of planning and to confirm numbers with venues given the continuing restrictions. Please contact academic.conferences@contacts.bham.ac.uk if there are any issues needing our attention.

---

The 12th International Conference on Position Sensitive Detectors will feature the latest developments in position sensitive detectors from leading researchers around the world and across a wide range of scientific disciplines. The conference has a strong multidisciplinary bias and encourages cross-fertilisation and transfer of ideas between researchers working in many different fields.

All sessions are plenary with each started by an overview presentation by a keynote speaker followed by research presentations relevant to that topic.

Keynote speakers (2021):

The provisional list of keynote speakers is: Helen Boston (Liverpool), Michael Campbell (CERN), Nicolo Cartiglia (INFN Torino), Cinzia Da Via (Manchester), Heinz Graafsma (DESY), Richard Hall-Wilton (ESS), Tomasz Hemperek (Bonn), Andrew Holland (Open University), Robert Johnson (Santa Cruz), Carl Wheldon (Birmingham), Gregor Kramberger (JSI Ljubljana), Eraldo Oliveri (CERN), Petra Riedler (CERN), Vincent Schoepff (CEA), Reinhard Schulte (Loma Linda) and Nicola Tartoni (DSL, RAL).

There will also be two days of industrial exhibitions and two days of poster presentations during the conference.

Further details on the previous conference hosted by the Open University can be found on the PSD11 Conference Website.

Due to current circumstances PSD12 will be offered in a “hybrid mode" (both in-person and virtual) with enhanced participation enabled for those only able to join remotely due to restrictions. Many more details can be found at the main conference web pages.

Paper submitted to the conference will be published through the Journal of Instrumentation with instructions for abstract submission also at the main conference web pages.

We look forward to welcoming you to Birmingham, the UK's second largest city and centre of the West Midlands, the region which in the 19th Century was the birthplace of the industrial revolution.

Scientific Themes

• X-ray and Gamma Ray Detectors

• Novel Ionising Radiation Detection Systems

• Position Sensitive Fast Timing Detectors

• Detectors for High Radiation and Extreme Environments

• Advances in Pixel Detectors and Integration Technologies

• Gas-based Detectors

• Medical Applications of Position Sensitive Detectors

• Detectors for Neutron Facilities

• Detectors for FELS, Synchrotrons and Other Advanced Light Sources

• Applications in Life Sciences and Biology

• Applications in Astronomy, Planetary and Space Science

• Applications in Security and Environmental Imaging

• Applications in Nuclear Physics and Nuclear Industry

• Applications in Particle Physics

• Applications in Astro-particle Physics

• Applications in Condensed Matter

Conference Poster

Conference web pages

Venue Current Risk Assessment Document

Sunday, 12 September

1 Informal Welcome (Edgbaston Park Hotel)

Hotel Web Pages

Monday, 13 September

Registration

2 Welcome by University of Birmingham Pro-Vice-Chancellor for Science and Engineering

Speakers: Prof. Stephen Jarvis (Pro-Vice-Chancellor. University of Birmingham), Philip Patrick Allport (University of Birmingham (UK)), Louise Walczak (University of Birmingham)

PSD12-Jarvis.pdf

Welcome Instructions.pdf

Detectors for FELS, Synchrotrons and Other Advanced Light Sources

Conveners: Nicola Tartoni, Philip Patrick Allport (University of Birmingham (UK))

3 Detectors for FELS, Synchrotrons and Other Advanced Light Sources

Speaker: heinz graafsma (DESY)

PSD12-graafsma.pdf

4 Timepix4 timestamping detector for synchrotron applications

Timepix4 is a versatile readout chip with 55 µm pixels, recently developed by CERN on behalf of the Medipix4 collaboration. It can operate both in a photon counting mode with frame readout, and a timestamping mode with event readout. Both of these modes offer higher performance than existing Medipix3 and Timepix3 chips. This makes Timepix4 appealing to a wide range of X-ray experiments at synchrotrons. For example, while X-ray diffraction experiments are normally done with framing detectors, the ability to switch to timestamping mode can offer extreme time resolution (down to individual synchrotron bunches) in experiments with moderate flux or specific regions of interest.

At DESY, a new readout system is being developed that is designed to cope with the chip’s high readout bandwidth (up to 162 Gbps per chip). Firstly, a single chip carrier board has been designed, produced and tested. The layout, flat and with the chip at the edge of the board, enables a number of experimental set-ups, and also allows for 2-chip tiled systems. For this first iteration, a commercially available readout board hosting a powerful Zynq UltraScale+ System on Chip has been chosen, due the large number of high speed transceivers available. Data is transferred to a control PC over Firefly optical links. Firmware and software development and chip testing are in progress.

In the long term, multi-megapixel systems composed of multiple chips will be developed. New detector head boards and also custom readout boards will be needed. Furthermore, recent developments on Through Silicon Via (TSV) technology will make it possible to operate the chip without wire bonds, thus greatly reducing the dead gaps between modules.

Speaker: David Pennicard (DESY)

DESY_Timepix4_PSD12_v3_upload.pdf

5 Prototype Characterization of a Charge-integrating Pixel Detector Readout Chip with In-pixel A/D conversion

The HYLITE (High dYmamic range Laser Imaging deTEctor) is a new hybrid pixel detector readout chip, which is designed for advanced light sources such as X-ray Free Electron Laser (XFEL) and diffraction-limited storage rings. These X-ray sources produce beams with high intensities, high repetition frequency and good coherence. In order to make use of these excellent properties, the detector system with higher dynamic range and readout speed is needed. HYLITE is a charge-integrating readout chip which has three gains for different dynamic ranges and automatic gain switching function. The full dynamic range covered by HYLITE is 1~10000 photons at 12keV for each pixel in every shot. In-pixel ADC is designed to achieve front-end digitalization and 10 kHz continuous frame rate.

HYLITE 0.1 is the first prototype chip designed using CMOS 0.13 mm technology to verify basic pixel functions. The pixel array consists of 6×12 pixels. The size of each pixel is 200μm×200μm and will be improved to 100μm×100μm in the future. Six different design variations of pixels with different integrating capacitance and structures were designed to help optimize between area and performance. The test results showed that the non-linearity of the pre-amplifier is 0.16%, 0.51%, and 1.11% in high, medium and low gain mode, respectively. A 10bits Wilkinson ADC is integrated in each pixel to digitalize the output of pre-amplifier. The linear feedback shift register (LFSR) is used as the ADC clock counter as well as the readout shifter for compacting the layout area. By front-end digitalizing, analog signal transmission of long distance is avoided and frame rate of 10 kHz was also tested and proved.

Speaker: Mujin LI (IHEP,CAS)

HYLITE_PSD12_Limj.pdf

6 Advancing the JUNGFRAU detector towards low-energy X-ray applications

The charge integrating hybrid silicon pixel detector JUNGFRAU has found widespread use for hard X-ray applications at free-electron laser (FEL) and synchrotron facilities. Equipped with three dynamic switching gains at pixel level, the most recent version of JUNGFRAU offers single photon resolution from at least 1.2 keV and a high dynamic range of $10^{4}$ 12 keV photons at a maximum frame rate of 2 kHz. The detector hardware is modular with a single module comprising 0.5 megapixels at a pixel size of 75 $\times$ 75 μm$^2$. Owing to the low noise performance, high dynamic range, position resolution, and easy scalability of the JUNGFRAU system, the detector is of high interest for applications in soft X-ray science.

Recently, a four-megapixel (4M) JUNGFRAU camera has been installed at the Maloja end station of the low energy beamline Athos of the Swiss free-electron laser (SwissFEL). The beamline operates at a photon energy range from 250 eV to 2 keV, making the current JUNGFRAU system applicable for experiments at the higher end of the available energy spectrum. At energies below ~1 keV, the readout capacitance of the hybrid detector limits the capability of resolving single photons. Signal amplification at sensor level could overcome this limitation and allow the JUNGFRAU system to significantly extend its low energy range.

In this contribution, we present first results of the Maloja JUNGFRAU 4M system, demonstrating the capabilities of the current detector version for soft X-ray science, and provide an outlook on efforts to couple the JUNGFRAU readout ASIC with LGAD sensors to achieve single photon resolution at energies below 1 keV.

Speaker: Dr Viktoria Hinger (Paul Scherrer Institut)

PSD12_JUNGFRAU_lowenergyXrays_upload.pdf

10:50 Coffee/Tea

7 Industrial Exhibition

(Same venue as catering provided)

Speakers: Tony Price (University of Birmingham (GB)), Louise Walczak (University of Birmingham)

Industrial Exhibitors and Sponsors

Gas-based Detectors 1

Conveners: Harry Van Der Graaf (Nikhef National institute for subatomic physics (NL)), Konstantinos Nikolopoulos (University of Birmingham (GB))

8 PSD and Micro Pattern Gas Detectors technologies

Micro Pattern Gas Detectors, used today in several experiments and applications, are recognized as a mature and successful technology. The ability to adapt to a wide range of requirements is offered by the variety of micro patterns solutions available, their reciprocal compatibility, the achieved skills in manufacturing processes and the continuous advancement in readout technologies. This aspect is a key ingredient behind the various and diversified R&D lines involving MPGD and behind the current dissemination of these technologies in numerous fields.

The keynote will try to highlight, via examples, possibilities and strategies in position sensitive detector based on MPGD technologies. Large prominence will be given to the readout stage, touching aspects that are not exclusives of MPGD technologies. Potential and promising future developments in the field will be outlined.

Speaker: Eraldo Oliveri (CERN)

PSD12_EOliveri_PSDandMPGD.pdf

9 Micromegas sectors for the ATLAS Muon Upgrade, towards the installation of the New Small Wheel in 2021

The ATLAS experiment is currently upgrading the first muon station in the high-rapidity region with the construction of new detector structures, named New Small Wheels (NSW), based on large-size multi-gap resistive strips Micromegas technology and small-strip Thin Gap Chambers (sTGC).
The NSW system will be installed in the ATLAS underground cavern during the LHC long shutdown 2 to enter in operation for Run3.
128 Micromegas quadruplets, each of which provides four measurements of a particle track, are needed to build the two New Small Wheels, covering a total active area of about 1280 m2. The construction of all MM modules, carried out in France, Germany, Italy, Russia and Greece, is completed. Their mechanical integration into sectors, the installation of on-detector services and electronics, for the first NSW is also completed, along with all validation and acceptance tests. The preparation of the second NSW is very well advanced.
The advanced status of the project, in view of the imminent installation of the two NSW in ATLAS by the fall of 2021 will be reported.
The presentation will describe the integration workflow of Micromegas detector into sectors and will focus on their cosmic rays results of the final validation tests.

Speaker: Luca Martinelli (Sapienza Universita e INFN, Roma I (IT))

PSD12_Martinelli.pdf

10 High rate capability studies of triple-GEM detectors for the ME0 upgrade of the CMS muon spectrometer

The high-luminosity LHC (HL-LHC) upgrade sets a new challenge for particle detector technologies. In the CMS muon system gaseous detectors, the increase in luminosity will produce a particle background ten times higher than at the LHC. To cope with the high rate environment and maintain performance, the triple-Gas Electron Multiplier (GEM) technology was chosen for the high-rate capable detectors for the CMS ME0 upgrade project in the innermost region of the forward muon spectrometer. An intense $R\&D$ and prototype phase is ongoing to verify that such technology meets the stringent performance requirements of highly efficient particle detection in the harsh background environment expected in the innermost ME0 region. We describe recent rate capability studies on triple-GEM detectors operated with an $Ar/CO_2 \, (70/30)$ gas mixture at an effective gas gain of $2 \times 10^4$ by using a high-intensity $22 \, \rm{keV}$ X-ray generator. In light of these rate capability studies, a novel foil design for the ME0 detectors was developed based on double-sided segmented GEM-foils and a high voltage distribution and filtering system. We describe the impact of the new design on detector performance and present a summary of ongoing R&D activities.

Speaker: Luis Felipe Ramirez Garcia (Universidad de Antioquia (CO))

FRamirez_PSD12_conference_rev.pdf

11 High-granularity optical and hybrid readout of gaseous detectors: developments and perspectives

Modern imaging sensors and ASICs allow for high-sensitivity pixellated readout of gaseous detectors with good spatial resolution. Advances towards ultra-high-speed imaging sensors, low noise characteristics and internal amplification in combination with increasing pixel counts make scintillation light readout well-suited for the most demanding applications ranging from radiation imaging and beam monitoring to track reconstruction techniques including hybrid approaches with optical and electronic readout.

Building upon high-resolution imaging with optically read out gaseous detectors using different MicroPattern Gaseous Detector (MPGDs) technologies, developments towards a low material budget beam monitoring detector will be presented. This development takes advantage of intuitive pixellated readout enabled by imaging sensors and the possibility to guide light with optical elements and mirrors to locate readout devices outside of the beam path for minimising radiation exposure and material budget.

While frame rate capabilities have previously limited optical readout to low event rates or integrated imaging, novel ultra-fast CMOS sensors offer unprecedented readout speeds at moderate resolution. This not only enables rapid fluoroscopy limited only by incident radiation flux and the high rate capabilities of MicroPattern Gaseous Detectors, but may also be used for recording image sequences resolving drift time differences along tracks in TPCs. Developments towards direct 3D track reconstruction in optical TPCs with ultra-fast CMOS readout will be shown along perspectives for negative ion optical TPCs for superior depth resolution.
In addition, alternative hybrid TPC readout approaches combining detailed 2D imaging with timing information from fast photon detectors such as SiPMs or transparent electronic readout electrodes are presented.

The combination of the flexibility of gaseous detectors including different target densities and large detection areas with state-of-the-art pixellated sensors offers unprecedented possibilities for rare event searches, beam monitoring and rapid, high-resolution imaging.

Speaker: Florian Maximilian Brunbauer (CERN)

OpticalReadoutPSD12.pdf

12 Studies on tetrafluoropropene-CO2 based gas mixtures for the Resistive Plate Chambers of the ALICE Muon IDentifier

Due to their simplicity and comparatively low cost, Resistive Plate Chambers are gaseous detectors widely used in high-energy and cosmic rays physics when large detection areas are needed. However, the best gaseous mixtures are currently based on tetrafluoroethane, which has the undesirable characteristic of a large Global Warming Potential (GWP) of about 1400 and, because of this, it is currently being phased out from industrial use. As a possible replacement, tetrafluoropropene (which has a GWP close to 1) has been taken into account.
Since tetrafluoropropene is more electronegative than tetrafluoroethane, it has to be diluted with gases with a lower attachment coefficient in order to maintain the operating voltage close to 10 kV. One of the main candidates for this role is carbon dioxide. In order to ascertain the feasibility and the performance of tetrafluoropropene-CO2 based mixtures, an R&D program is being carried out in the ALICE collaboration, which employs an array of 72 Bakelite RPCs (Muon Identifier, MID) in order to identify muons. Different proportions of tetrafluoropropene and CO2, with the addition of small quantities of isobutane and sulphur hexafluoride, have been tested with 50x50 cm2 RPC prototypes with 2 mm wide gas gap and 2 mm thick Bakelite electrodes.
In the presentation, results from tests with cosmic rays will be presented, together with data concerning the current drawn by a RPC exposed to the gamma-ray flux of the Gamma Irradiation Facility (GIF) at CERN. Moreover, a beam test at GIF is scheduled in July, 2021 and some of its preliminary results will be shown.

Speaker: Alessandro Ferretti (Universita e INFN Torino (IT))

2021-09-07-PSD12.pdf

2021-09-07-PSD12.pptx

13:05 Lunch

Applications in Particle Physics 1

Conveners: David Smith (Brunel University London), Laura Gonella (University of Birmingham (UK))

13 Novel Ionising Radiation Detector Systems

Speaker: Cinzia Da Via (University of Manchester (GB))

Future Detectors Systems-12th September.pdf

14 Status of the upgrade project of the CMS Tracker for HL-LHC

The CMS experiment is currently preparing the upgrade of the tracking system for the High-Luminosity LHC operations (HL-LHC), scheduled to start in 2027, which ultimately will bring the instantaneous luminosity up to 7.5x10$^{34}$ cm$^{−2}$ s$^{−1}$. To achieve its physics goals the new detector needs to include selectively tracking information in the first level trigger stage and improve the tracking resolution while operating at up to 200 interactions per beam crossing and up to 4000 fb$^{-1}$ of integrated luminosity over a decade. In this talk, the layout of the new detector, the main technological choices together with highlights on the current status of the main detector components will be presented.

Speaker: Ernesto Migliore (Universita e INFN Torino (IT))

em20210913_v4.pdf

15 Module development for the ATLAS ITk Pixel Detector

In HL-LHC operation the instantaneous luminosity will reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. The current ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The innermost part of ITk will consist of a state-of-the-art pixel detector.
Several different silicon sensor technologies will be employed in the five barrel and endcap layers.
Based on first modules assembled using the RD53A prototype readout chip, numerous issues are being studied. These include production issues like bump bonding of large area, thin modules, as well as layout issues like optimization of the bandwidth and sharing of links between multiple chips and modules. The talk will present results of many of these studies, which directly impact the construction and assembly of modules with using the first production version of the readout chip ITKpixV1, which will become available shortly

Speaker: Kenneth Wraight

Kenneth Wraight.pdf

Kenneth Wraight.pptx

16 The Silicon Vertex Detector of the Belle II Experiment

In 2019 the Belle II experiment started data taking at the asymmetric SuperKEKB collider (KEK, Japan) operating at the Y(4S) resonance. Belle II will search for new physics beyond the Standard Model by collecting an integrated luminosity of 50 ab-1.
The Silicon Vertex Detector (SVD), consisting of four layers of double-sided silicon strip sensors, is one of the two vertex sub-detectors. The SVD extrapolates the tracks to the inner pixel detector (PXD) with enough precision to correctly identify hits in PXD belonging to the track. In addition the SVD has standalone tracking capability and utilizes specific ionization to enhance particle identification in the low momentum region.
The SVD is operating reliably and with high efficiency, despite exposure to the harsh beam background of the highest peak-luminosity collider ever built. High signal-to-noise ratio and hit efficiency have been measured, as well as the precise spatial resolution; all these quantities show excellent stability over time. Data-simulation agreement of some discrepancy on cluster properties has recently been improved through a careful tuning of the simulation. The precise hit-time resolution can be exploited to reject out-of-time hits induced by beam background, which will make the SVD more robust against higher levels of backgrounds.
During the first three years of running, radiation damage effects on strip noise, sensor currents, depletion voltage, have been observed, as well as some coupling capacitor failure due to intense radiation bursts. None of these effects cause significant degradation in the detector performance.

Speaker: Giulio Dujany

gdujany_PSD12.pdf

17 The ATLAS AFP Proton Spectrometer (in-person)

A key focus of the physics program at the LHC is the study of head-on proton-proton collisions. However, an important class of physics can be studied for cases where the protons narrowly miss one another and remain intact. In such cases the electromagnetic fields surrounding the protons can interact producing high energy photon-photon collisions, for example. Alternatively, interactions mediated by the strong force can also result in intact forward scattered protons, providing probes of quantum chromodynamics (QCD).

In order to aid identification and provide unique information about these rare interactions, instrumentation to detect and measure protons scattered through very small angles is installed in the beam-pipe far downstream of the interaction point. We describe the ATLAS Forward Proton `Roman Pot' Detectors (AFP and ALFA), including their performance to date and expectations for the upcoming LHC Run 3, covering Tracking and Time-of-Flight Detectors as well as the associated electronics, trigger, readout, detector control and data quality monitoring. The physics interest, beam optics and detector options for extension of the proogramme into the High-Luminosity LHC (HL-LHC) era are also discussed.

Speaker: Paul Richard Newman (University of Birmingham (GB))

PSD21.pdf

15:50 Coffee/Tea

Medical Applications of Position Sensitive Detectors 1

Conveners: Tony Price (University of Birmingham (GB)), Konstantin Stefanov (University of Oxford (GB))

18 Medical Applications of Position Sensitive Detectors

Speaker: Prof. Reinhard Schulte (LLU)

PSD12-abstract-Sep 13 2021.pdf

RWS_PSD12_09-13-21.pdf

19 MONOLITH – pico-second time-stamping in fully monolithic highly-granular pixel sensors

The MONOLITH H2020 ERC project aims at the development of fully monolithic highly granular pixel sensors with pico-second time-stamping capabilities. Using high-resistivity epitaxial layer material in combination with a continuous deep and thin gain layer, a pico-second fast detector response is achieved over the full pixel cell. The placement of the gain layer away from the pixel junctions additionally allows for a small pixel pitch of down to 50 micrometers, resulting in a high spatial precision. Making use of silicon-germanium BiCMOS technology, a ultra-fast and low noise front end has been implemented inside a large collection electrode design.
Various prototypes of this technology have been produced with different variations, including various doping levels and different complexity of in-pixel circuitry. The prototypes have been investigated in laboratory and test-beam measurements, with a focus on the sensor gain, time-stamping capability and detection efficiency.
This contribution will introduce the novel sensor concept and discuss the front-end that has been implemented in the SiGe BiCMOS technology. Results of laboratory measurements with radioactive sources will be presented, including measurements of the sensor gain with an iron source and timing measurements that have been performed with a strontium source.

Speaker: Magdalena Munker (CERN)

monolith_psd_2021_mmunker.pdf

20 Position sensitive detectors in proton therapy: online monitoring of the beam position

In the last decades, the number of Proton Therapy centers has increased substantially in Asia, in the US and lately in Europe. The characteristics of the Bragg-peak allows precise longitudinal confinement of the prescribed dose to the tumor. Laterally, this is achieved by using narrow pencil beams to scan the tumor volume. This however requires precise control of the position in the plane perpendicular to the beam axis (by means of scanning magnets), enabling high treatment quality.

The Center for Proton therapy at PSI operates a strip ionization chamber (position sensitive detector) to monitor the pencil beam position for safety reasons as one of the final beamline elements. Emphasis of the PSD design was on high robustness due to quasi-continuous usage, but low in maintenance – a detector breakdown is a showstopper for daily patient treatments. Using online beam position monitoring as a safety feature, fast signal generation, processing and transfer to the control system are required.

The beam position detector in one of our Gantries operated stable and well for almost ten years, but the now outdated front-end electronics and dwindling stock parts call for maintenance work. This is an opportunity to upgrade our position detector with a new chip (ADAS from analog devices), adding new features to the detector (sampled readout, online gain control). The task brings a challenging replacement procedure along, as this is the first maintenance work since its commissioning ten years ago.

This contribution intends to give an introduction into one of the proton therapy facilities at PSI. The main topic covers the task of online beam monitoring with a planar strip ionization chamber in a clinical environment and the imposed demands with emphasis on detector design and signal processing. Eventually, upgrading and exchanging this position detector in our clinical environment will be detailed.

Speaker: Robert Michael Schäfer (PSI - Paul Scherrer Institut)

Position_Sensitive_detectors_clinical_forPubl.pdf

21 Upstream MLC leaf position detection in complex radiotherapy fields

Multileaf collimators (MLC) are an integral component in modern radiotherapy as they dynamically shape the MV photon treatment field and therefore need to be closely monitored to ensure correct treatment delivery. Currently, MLC leaves are calibrated to ±1 mm every 3 months, however leaves can drift beyond this during calibration dates and treatment verification only occurs post-treatment. MAPS detectors are radiation hard for photon and electron irradiation, have high readout speeds and low attenuation which makes them ideal upstream radiation detectors. Previously, we reported on leaf position reconstruction for single leaves using the Lassena, a 12x4 cm2, three side buttable MAPS suitable for clinical deployment. Sobel filter-based methods were used for edge reconstruction. It was shown that correspondence between reconstructed and set leaf position was excellent and resolutions ranged between 60.6±8 and 109±12 μm for a single central leaf with leaf extensions ranging from 1 to 35 mm using 0.3 sec of treatment beam time. Here, we report on leaf edge reconstruction using Sobel filter-based methods in complex leaf configurations, as in clinical use with extensions ranging up to 120 mm. The Lassena detector was placed in the treatment field of an Elekta Agility LINAC with MLC leaves of width 0.5 cm extended into the field creating various leaf configurations. Results show that leaf positions can be reconstructed with resolutions between 78±7 and 149±14 μm at the iso-centre using 0.15 sec long treatment segments. These resolutions significantly exceed current calibration standards.

Speaker: Mr Jordan Pritchard (University of Bristol)

Jordan_Pritchard_PSD12_2021_Presentation_Public.pdf

22 LGAD-based detectors for monitoring therapeutic proton beams

Purpose. Two prototypes for beam monitoring in particle therapy are being developed based on LGAD technology, aiming at improving and enriching the performances of state-of-the-art gas detectors. The results of tests on clinical proton beams are presented.
Methods. A proton counter for online fluence beam monitoring is made of sensors featuring 3.0x0.5 $cm^2$, 30 strips (150 $\mu$m pitch), 50 $\mu$m active thickness, readout using 40 dB amplifiers and a 5 Gs/s digitizer. Counting inefficiencies due to signal pile-up are mitigated combining two neighboring strips counts. A 2.7x2.7 $cm^2$ sensor (146 strips) with dedicated front-end board, readout with FPGAs, will be the final counter at the project end. The second prototype sets two thinned sensors (70 $\mu$m total thickness, 11 strips of 2.2 $mm^2$ area each) in a telescope for measuring the Time of Flight (ToF) and derive the beam energy. The signals are readout through dedicated front-end boards, acquired with a 5Gs/s digitizer and processed with MALTAB. A high-precision positioning system allows changing the sensors relative distance in the telescope with 10 $\mu$m precision. The counter prototype was tested at Trento Proton Therapy Center (Italy) at different beam energies with different beam currents, while the ToF prototype was tested at both Trento and CNAO (Pavia, Italy).
Results. The error on the counting efficiency is < 1% up to a proton fluence rate of 1x$10^8$ Hz/$cm^2$ and, after pile-up corrections, 5x$10^8$ Hz/$cm^2$. A calibration procedure of the telescope prototype allows measuring the beam energy with deviations of a few hundred keV for most of the energies in the clinical range (60-230 MeV), corresponding to less than 1 mm range difference.
Conclusion. Preliminary tests of LGAD sensors segmented in strips demonstrate their capabilities as beam monitors, for both counting and beam energy measurement purposes. Future required developments will be reported.

Speaker: Dr Anna Vignati (Università degli Studi di Torino and INFN - National Institute for Nuclear Physics)

Vignati_PSD2021_Tuesday.pdf

23 Reception at Industrial Exhibition

Speaker: Louise Walczak (University of Birmingham)

Industrial Exhibitors and Sponsors

Tuesday, 14 September

Applications in Astronomy, Planetary and Space Science 1

Conveners: Konstantinos Nikolopoulos (University of Birmingham (GB)), Philip Patrick Allport (University of Birmingham (UK))

24 Applications in Astronomy, Planetary and Space Science (in-person)

Speaker: Andrew Holland (The Open University)

PSD12 - Detectors for Space Science.pdf

PSD12 - Detectors for Space Science.pptx

25 Development of a Penetrating particle ANalyzer for high-energy radiation measurements in space

The Penetrating Particle Analyzer (PAN) is an instrument conceived to precisely measure the flux, composition and arrival direction of highly penetrating particles in space of energy ranging from 100 MeV/n to 20 GeV/n. Precise measurements of their energy spectra and composition are of great interest to study Solar Modulation of Cosmic Rays, to characterise SEPs, as well as the radiation environment around planets and to improve Space Weather predictions for Deep Space travels.
The design is based on a modular magnetic spectrometer of small size, reduced power consumption and weight which make it suitable for deep space and interplanetary missions. The high-field permanent magnet sectors are instrumented with high resolution silicon micro-strip detectors, Time-OF-Flight scintillator counters readout by SiPMs, and active Pixel detectors to maintain the detection capabilities in high rate conditions occurring during solar energetic particle events (SEPs) or when traversing radiation belts around planets. After the description of the PAN instrument, the development and tests of the mini.PAN demonstrator will be presented in this contribution.

Speaker: Philipp Azzarello (Universite de Geneve (CH))

PAN_PSD12_v1r2.pdf

26 Review of position sensing techniques in space-based particle instruments (in-person)

Position sensing techniques are extensively used in space-based particle instruments for the detection of space plasmas and energetic particle radiation. Such instruments typically consist of electrostatic analysers at the low end of the energy range and solid state/scintillation detectors at the higher energy end. With a need for large fields-of-views and all-sky particle imaging, high resolution, low resource, position sensing detection systems are in increasing demand for these instruments. This paper will review position sensing techniques typically employed on space missions in the past, present future instrument requirements and discuss potential exploitation of emerging technologies.

Speaker: Prof. Dhiren Kataria (Mullard Space Science Laboratory, University College London)

Position sensitive detectors for space particle instruments final.pdf

Position sensitive detectors for space particle instruments final.pptx

27 The application of the Rasnik 3-point alignment system in seismic instrumentation (in-person)

For high-precision measurement of the momentum of muons, the alignment of three (inner, middle and outer) muon tracking detectors, placed at some mutual distance in the magnetised volume, is essential. Since accurate alignment can not be realised mechanically, the alignment is continuesly monitored instead. For this, a back-illuminated coded mask is attached to the inner detector, and a positive lens, attached to the middle detector, projects an image of the mask pattern onto an image pixel sensor attached to the outer detector. The images from the sensor are analysed and contain high-precision info about the alignment. By correcting the measured muon sagittas with alignment data, the actual positions of the three muon trackers is no longer relevant.
Since 2008, some 8000 Rasnik systems are operational in the ATLAS experiment. The data suggests a much higher operational precision than the original ATLAS requirement of order 10 microns.
Simulations have revealed that spatial resolutions of order 1 nm per image can be expected, and that this precision is only limited by the quantum fluctuations of the light detected by the pixels of the image sensor. This precision was confirmed by a measurement using the MERCURY-41-302 sensor.
By replacing the positive singlet lens by a microscope objective (Newport M-20X), the magnification lever arm is expected to amplify the image displacement by a factor 20. With 275 fps, a value of 7 pm /sqrt(Hz) has been reached, and by applying new hardware a value of 0.2 pm /sqrt(Hz) is expected. As a simple and straightforward 2D displacement monitor, Rasnik could be applied in the seismic instruments used in Gravitational Wave detectors, replacing commonly used interferometers.

Speaker: Harry Van Der Graaf (Nikhef National institute for subatomic physics (NL))

Rasnik.pdf

Rasnik.pptx

28 Review of single photon imaging techniques with fast timing for applications in space and particle physics, and the life sciences (in-person)

There is an increasing demand for photon counting detectors capable of time-resolved imaging in many fields. In this paper we review the available detector and electronic technologies available and under development for applications such as Cherenkov imaging in particle physics and gamma-ray astronomy, and for wide-field fluorescence lifetime imaging in the life science field. While traditional vacuum tube devices such as the microchannel plate image intensifier still offer state of the art timing performance, the recent and rapid development of silicon photomultipliers, single photon avalanche detector arrays, and other hybrid devices are providing ever stronger competition. Advances in multichannel ASIC electronics for high throughput multichannel waveform capture and time to digital conversion have kept up with detector development and systems with 100 Mcount/s throughput at sub-100 ps single photon timing are becoming realistic. We discuss the requirements of various applications in terms of imaging, time resolution and throughput and compare the advantages and disadvantages of the competing technologies.

Speaker: Prof. Jon Lapington (University of Leicester)

PSD12 - Review of single photon imaging techniques.pdf

10:50 Coffee/Tea

29 Industrial Exhibition

(Same venue as catering provided)

Speakers: Tony Price (University of Birmingham (GB)), Louise Walczak (University of Birmingham)

https://www.birmingham.ac.uk/facilities/mds-cpd/conferences/psd12/industrial-exhibitors.aspx

Position Sensitive Fast Timing Detectors 1

Conveners: Laura Gonella (University of Birmingham (UK)), Peter Hobson (Queen mary University London)

30 Position Sensitive Fast timing Detectors

Speaker: Nicolo Cartiglia (INFN Torino (IT))

Position_sensitive_timing.pdf

Position_sensitive_timing.pptx

31 Optimization of gain layer doping, profile and carbon levels on HPK and FBK sensors

Low Gain Avalanche Detectors (LGADs) are thin silicon detectors (ranging from 20 to 50 um in thickness) with moderate internal signal amplification (up to a gain of ~50). LGADs are capable of providing measurements of minimum-ionizing particles with time resolution as good as 17 pico-seconds. In addition, the fast rise time (~500ps) and short full charge collection time (~1ns) of LGADs are suitable for high repetition rate measurements in photon science and other fields. The first implementation of this technology will be with the High-Granularity Timing Detector (HGTD) in ATLAS and the Endcap Timing Layer (ETL) in CMS for the high luminosity upgrade at the Large Hadron Collider (HL-LHC). The addition of precise timing information from LGADs will help mitigate the increase of pile-up and improve the detector performance and physics sensitivity. Past publications have proven the vast improvement in term of radiation hardness of deep gain layer and carbon implantation in LGAD designs. In this contribution a study will be shown on the tuning of the doping concentration in the deep gain layer of HPK sensors to optimize the performance before and after radiation damage. Furthermore the effect of the combination of a deep gain layer and carbon implantation in FBK sensors will be shown alongside an optimization of the carbon concentration level. Results on electrical properties and charge collection will be shown on pre and post irradiation. Sensors were irradiated at JSI (Ljubljana, Slovenia) with neutrons and at CYRIC (KEK, Japan) with protons, then tested using the beta-scope setup and probe stations at UCSC.

Speaker: Dr Simone Michele Mazza (University of California,Santa Cruz (US))

170821_PSD12_LGAD_radhard.pdf

32 Timing and spatial performance of IHEP AC-LGADs

AC-coupled Low- Gain Avalanche Detectors (AC-LGAD) are designed as detectors with 100% fill factor for high precision 4D-tracking, which have been studied and researched by many institutes including BNL、FBK et al. Their results show that timing resolution of AC-LGAD can be lower than 50ps and spatial resolution can be better than 10um. Standard LGAD sensors of the Institute of High Energy Physics (IHEP) already showed time resolution better than 35ps before irradiation. Recently IHEP developed our first AC-LGAD sensors. This talk will present the simulation and latest testing results about 50um thick IHEP AC-LGAD sensors. Simulation studies of process parameters including the n+ layer dose and oxide thickness and their effect to signal shape will be shown. Meanwhile, simulation studies about charge sharing between AC-LGAD pixels with different pad-pitch structures will also be shown. Time resolution for the sensors tested by using Beta source are better than 50ps which is close to standard LGADs with similar gain. Spatial resolution of sensors with different pad-pitch structures tested by using laser system will also been shown.

Speaker: Dr Mei Zhao (Chinese Academy of Sciences (CN))

Timing and spatial performance of IHEP AC-LGADs_v2_MeiZhao_20210914.pdf

33 Overview of CNM LGAD results with B, Ga and C diffused Si-on-Si and epitaxial wafers (in-person)

Low Gain Avalanche Detectors (LGADs) are n-on-p silicon sensors with an extra doped p-layer below the n-p junction which provides signal amplification. When the primary electrons reach the amplification region new electron-hole pairs are created that drift towards the p+ region increasing the generated signal. The moderate gain of these sensors, together with the relatively thin active region, provide excellent time performance for minimum ionization particles. To mitigate the effect of pile-up at the HL-LHC by both the ATLAS and CMS experiments have chosen the LGAD technology for their High Granularity Timing Detector (HGTD) and for the End-Cap Timing Layer (ETL) respectively. A full characterization of LGAD sensors fabricated at CNM before and after neutron irradiation up to 2.5E15 neq/cm2 will be presented. Sensors produced in epitaxial and Si-on-Si wafers and doped with Boron and Gallium and also diffused with Carbon have been studied. The results include their electrically characterization (IV, CV and bias voltage stability) and performance studies with a Sr-90 radioactive source setup. Also the behaviour of the Inter-Pad region for 2x2 LGAD arrays with Transient Current Technique (TCT) at different fluences will be shown.

Speaker: Chiara Grieco (Istitut de Fisica d'Altes Energies (IFAE) - Barcelona (ES))

OverviewCNM_CGrieco_PSD12.pdf

34 A High-Granularity Timing Detector for the ATLAS Phase-II upgrade

The increase of the particle flux (pile-up) at the HL-LHC with instantaneous luminosities up to L ~ 7.5 × 10^34 cm^-2s^-1 will have a severe impact on the ATLAS detector reconstruction and trigger performance. The end-cap and forward region where the liquid Argon calorimeter has coarser granularity and the inner tracker has poorer momentum resolution will be particularly affected. A High Granularity Timing Detector (HGTD) will be installed in front of the LAr end-cap calorimeters for pile-up mitigation and luminosity measurement.

The HGTD is a novel detector introduced to augment the new all-silicon Inner Tracker in the pseudo-rapidity range from 2.4 to 4.0, adding the capability to measure charged-particle trajectories in time as well as space. Two silicon-sensor double-sided layers will provide precision timing information for minimum-ionising particles with a resolution as good as 30 ps per track in order to assign each particle to the correct vertex. Readout cells have a size of 1.3 mm × 1.3 mm, leading to a highly granular detector with 3.7 million channels.
Low Gain Avalanche Detectors (LGAD) technology has been chosen as it provides enough gain to reach the large signal over noise ratio needed.

The requirements and overall specifications of the HGTD will be presented as well as the technical design and the project status. The on-going R&D effort carried out to study the sensors, the readout ASIC, and the other components, supported by laboratory and test beam results, will also be presented.

Speakers: Simone Michele Mazza (University of California,Santa Cruz (US)), Hasko Stenzel (Justus-Liebig-Universitaet Giessen (DE))

170821_PSD12_HGTD.pdf

13:05 Lunch

Applications in Nuclear Physics and Nuclear Industry; X-ray and Gamma Ray Detectors 1; Medical Applications of Position Sensitive Detectors 2

Conveners: Konstantin Stefanov (University of Oxford (GB)), Paul Richard Newman (University of Birmingham (GB))

35 Applications in Nuclear Physics and Nuclear Industry (in-person)

Speaker: Carl Wheldon (University of Birmingham)

abstract.pdf

wheldon_nuclear_detectors_and_facilities_bham.pdf

36 Development of muon scattering tomography for a detection of reinforcement in concrete

Inspection of ageing, reinforced concrete structures is a world-wide
challenge. Existing evaluation techniques in civil and structural engineering have limited penetration depth and don’t allow to precisely ascertain the configuration of reinforcement within large concrete objects. The big challenge for critical infrastructure (bridges, dams, dry
docks, nuclear bioshields etc.) is understanding the internal condition of
the concrete and steel, not just the location of the reinforcement.
Muon scattering tomography is a non-destructive and non-invasive
technique which shows great promise for high-depth 3D concrete imaging.
A method was presented to locate reinforcement placed in a large-scale
concrete object. The reinforcement was simulated as two layers of 2 m long bars,
forming a grid, placed at a fixed distance from each other inside a large concrete
block. The technique exploits the periodicity of the bars in a reinforcement grid
by considering the Fourier-transformed signal. The presence of a grid leads to
peaks in the normalized Fourier frequency spectrum. Peaks locations are determined by the grid spacing and their amplitude by the bar diameters. It is
therefore possible to estimate both bar diameter and spacing with this method.
Using only one week worth of data taking, bars with a diameter of 7 mm and
larger, could easily be detected for a 10 cm spacing. The signal for 6 mm diameter bar exceeds the background and but becomes very clear after two weeks
of data taking. Increasing the spacing to 20 cm results in a smaller amount
of iron in the scanning area, thus longer data taking is required. It has been
shown that this method enables the detection of the smallest bars in practical
use within one or two weeks of data taking time and standard spacing. This is
a very important result for non-destructive evaluation of civil structures.

Speaker: Magdalena Dobrowolska (University of Bristol)

Dobrowolska_talk.pdf

37 Proton CT application in X-CT calibration for treatment planning in proton therapy

Treatment planning systems for proton therapy require accurate information about stopping power ratio (SPR), relative to water, of the biological tissues the patients are made of. This information, in the present clinical practice, are extracted from X-rays computed tomography (X-CT) images. In this context the inaccuracy introduced in the conversion between Hounsfield Units (HU) and SPR maps is one of the main sources of uncertainty on the estimated proton range limiting the accuracy of treatment planning. In the recent past, in the framework of INFN funded research projects, a 5x20 cm2 field of view proton CT (pCT) system, composed of a microstrip silicon tracker and a YAG:Ce calorimeter, has been built with the aim to directly measure SPR maps. Proton tomographies of test phantoms acquired with this apparatus at Trento Proton Therapy Centre showed an accuracy on SPR measurement of about 1% (2020, Phys. Med. Biol. 65 225012). Recently a novel X-CT calibration technique, that makes use of the INFN pCT apparatus, has been proposed to improve X-CT calibration accuracy (2021, Med. Phys. 48 (3) 1349-1355). The aim of this project (XpCalib) is to prepare a set of biological phantoms and to acquire both pCT and X-CT scans on each of them by the pCT and X-CT systems to eventually extract a SPR-HU calibration function. The use of biological phantoms is proposed instead of synthetic tissue equivalent materials, which fail in accurately mimicking the real biological tissues’ properties. Another aspect that will be investigated is the possibilities to stabilize those phantoms, in order to be able to extend the calibration procedure to other proton therapy centers, even to those not equipped with a pCT scanner. In this contribution the proposed calibration method will be presented together with the main results of the pCT system.

Speaker: Monica Scaringella (INFN Firenze (IT))

Scaringella_PSD12.pdf

38 Characterization of a large LGAD sensor for proton counting in particle therapy

Purpose:
Based on LGAD technology, a fast proton counter prototype is being developed for the online monitoring of the fluence rate of therapeutic proton beams. The laboratory characterization of dedicated LGAD sensors segmented in strips covering an area of 2.7x2.7 cm^2 is reported.
Methods:
The LGAD sensor is segmented into 146 strips (160 um width, 26260 um length, 180 um pitch, 2 strips without gain, 144 strips with gain, and a nominal inter-strip distance of 66 um). A dedicated production at Fondazione Bruno Keeler (FBK, Trento, Italy) in 2020 consisted of 14 wafers with two different active thicknesses (55 um Si-Si wafers, 45 um for the Epi ones), with shallow gain implants, two p-gain doses, boron- low diffusion, co-implanted with a dose of carbon to improve the radiation resistance. Laboratory characterization of this production was performed at the University of Torino and at FBK, using a probe station, connected with a power devices analyzer for static DC electrical test, and the TCT to study dynamic properties of our sensors.
Results:
A global yield ratio between working strips over the total number of strips measured in the entire production of 89.4% and a mean breakdown voltage for good sensors (sensors without bad strips) measured on the backplane of about 212 V were found. The average full depletion voltage obtained was 22.12-23.47 V and 34.98 V for Si-Si and Epi wafers, respectively. Furthermore, the ratio between the 90/10 percentile for the leakage current at 160 V was lower than 1.6 for all the cases. The inter-strip distance measured was 80.8 um, 22% larger than the nominal no-gain distance, as previously observed by other groups.
Conclusion: 
The laboratory characterization showed good results and prepared the groundwork for the selection of the best set of sensors to be tested on clinical proton beams.

Speaker: Oscar Ariel Marti Villarreal (INFN - National Institute for Nuclear Physics)

PSD_Oscar_Marti.pdf

15:40 Coffee/Tea

Detectors for Neutron Facilities; Gas-based Detectors 2

Conveners: Paul Richard Newman (University of Birmingham (GB)), Konstantinos Nikolopoulos (University of Birmingham (GB))

39 Detectors for Neutron Facilities

Speaker: Richard Hall-Wilton (ESS - European Spallation Source (SE))

210914_PSD12_RJHW.pdf

40 Composite GYAGG-based scintillation screen for neutron detection

The present work deals with obtaining neutron sensitive scintillation screens and their evaluation. We have used cerium doped garnet Gd1.2Y1.8Ga2.5Al2.5O12:Ce (GYAGG) as a scintillator since quaternary garnets with the optimized ratio of cations have demonstrated high light yield under γ-quanta and α-particles excitation, 50 000 ph/MeV and 12 000 ph/MeV respectively, with fast decay time (~50 ns).
We have performed modelling of α-particles and tritons absorption in GYAGG and 6LiF using GEANT 4 software. Then the pathlengths of these particles in GYAGG and 6LiF media were estimated, allowing to calculate of the desired sizes of the scintillator and 6LiF particles and distances between them.
Translucent GYAGG ceramic tablets were prepared and grounded to the required particle size to obtain scintillation pigment. Screens samples with dimensions of 12x12x0.2 mm and phosphor density of ~50 mg/cm2 with the filling of 90% vol were prepared for light yield evaluation tests under α-particles. 241Am was used as an α-particles source. Scintacor ND neutron screen (6LiF/ZnS:Ag-based) was used as a reference. Pulse height spectra were recorded and peak positions were found to be ~ 900 channel for ND screen, and ~111 for GYAGG milled ceramics. ZnS(Ag) light yield under a-particles is known to be 49400 ph/MeV, so considering different PMT efficiency at the emission wavelengths of ZnS(Ag) and GYAGG:Ce3+, we can conclude that the light output of samples made of GYAGG milled ceramics is about 9700 ph/MeV.
The samples for tests under neutrons were prepared according to the simulation results. The composition was: 10 vol.% of scintillator, 30 vol.% of 6LiF, 60 vol.% of a binder. Phosphor layer density was 20 mg/cm2. Pulse height spectra were recorded against the reference screen (Scintacor ND). The total counts in neutron spectra for our best sample and the reference sample were found to be 321 and 299 respectively.

Speaker: Dr Ilia Komendo (NRC "Kurchatov Institute" - IREA (RU))

PSD_Komendo_14.09.2021.pdf

PSD_Komendo_14.09.2021.pptx

41 Development and characterization of a novel alpha particle SOI pixel sensor for neutron detection

Solid-state sensors have been initially proposed as direct replacement of $^3He$ gas detectors but recently raise the interest in imaging systems.
We have developed a monolithic sensor with high spatial granularity in SOIPIX technology for the detection of alpha particles of energy compatible with the reaction products of neutrons with converter materials. The chipset is composed by the main pixel matrix and the test structures needed for a better understanding of the chip functionality and for studying the electronic tuning strategies. The fabricated prototypes have been recently delivered and the first tests under alpha source have been performed.
We will present the proposed devices and the results of the experimental characterization.

Speaker: Dr Roberto Mendicino (Fondazione Bruno Kessler (FBK))

ppt_PSD.pdf

42 GridPix: the ultimate electron detector for TPCs (in-person)

By means of “Integrated Grid” InGrid MEMS technology, a MicroMegas is created on top of the (spark protected) TimePix-3 chip. Units containing four chips “Quads” and their services (data and control transfer, power, cooling) can be placed together, forming an arbitrarily large active direction area. Data from UV laser tracks, from cosmic ray muons, and from test beams are presented.
By applying 1.4 % CS2 in the gas, the drifting electrons form drifting negative ions of which the two drift velocities are measured with high precision. Negative ion TPCs can self-provide Tzero for tracks, which is convenient in rare-event experiments.
An outlook is presented on applying the future TimePix-4 in the electron GridPix detector.

Speaker: Harry Van Der Graaf (Nikhef National institute for subatomic physics (NL))

GridPix-PSD12.pdf

GridPix-PSD12.pptx

43 High Granularity Resistive Micromegas for high particle rates environment.

We present the latest performance studies of high-granularity resistive Micromegas (MM) detectors for tracking applications in high-rate environment. Nowadays MM are being used as tracking detectors in HEP experiment upgrades as in ATLAS experiment at LHC. To fulfill the requirements of stable and efficient operations up to particle fluxes as high as 10 MHz/cm2 coming from future High Energy Physics experiments, we produced and characterized several prototypes of resistive MM detectors with high granularity readout plane, with 1x3 mm2 size pads, and different resistive protection schemes, exploiting a pad-patterned layer or two uniform Diamond Like Carbon (DLC) layers.
In the pad-patterned layout each pad is totally separated from the neighbors. The anode pads are overlaid by resistive pads, both interconnected by intermediate “embedded” resistors.
In the double uniform resistive layers layout, each layer is obtained by a thin sputtering deposition of DLC on insulating foils. The two resistive layers are interconnected between them and to the readout pads with a network of conducting links with a few mm pitch, to evacuate the charge.
Characterization, performances, and stability studies of many prototypes have been carried out by means of radioactive sources, X-Rays, and particle beams. A comparison of the performance obtained with the different resistive layouts is reported, focusing on the response under high irradiation and high-rate exposure leading to an assessment of their potential. To cope with the high number of readout channels and allow for the size scalability of the detector avoiding dead areas, we are studying the integration of the readout electronics in the back of the detector. Preliminary results obtained with the first prototype with embedded front-end chip will also be presented.

Speaker: Massimo Della Pietra (Universita e sezione INFN di Napoli (IT))

PSD21_MDP_20210914.pdf

National Organising Committee Only: (Venue and zoom details to be confirmed)

Convener: Philip Patrick Allport (University of Birmingham (UK))

National Organising Committee Only

44 BBQ at the Mason Lounge and Garden, University of Birmingham

14th September. From 18.30: BBQ at the Mason Lounge and Garden, University of Birmingham (between R15 and R16 in the red zone on the attached map).

edgbaston-campus-map-BBQ.pdf

Wednesday, 15 September

Poster Set-up

Conveners: Louise Walczak (University of Birmingham), Tony Price (University of Birmingham (GB)), Philip Patrick Allport (University of Birmingham (UK))

How to video for poster presenters.mp4

Virtual Poster Session Login

Advances in Pixel Detectors and Integration Technologies I

Conveners: Helen Boston, Philip Patrick Allport (University of Birmingham (UK))

45 Advances in Pixel Detectors

Speakers: Tomasz Hemperek (University of Bonn (DE)), Tomasz Hemperek (University of Bonn (DE))

AdvancesInPixelDetectors_PSD21.pdf

46 Characterization of planar and 3D pixel sensors for the inner tracker of the CMS experiment (in-person)

The Compact Muon Solenoid (CMS) experiment is expected to collect an integrated luminosity of 3000 or even 4000fb^-1 in the ultimate scenario during the High Luminosity phase of the Large Hadron Collider (HL-LHC). This scenario comes with a high number of collisions per bunch crossing, and in turn, a high level of radiation for the inner layer of the CMS tracker. The simulations estimate a 1-MeV neutron equivalent fluence, phi_eq, of 2.3\times 10^16 cm^-2 at a distance of 2.8 cm from the collision point (for the integrated luminosity of 3000 fb^-1). The inner tracker of the CMS detector is required to withstand this range of fluence and maintain its track-finding functionality.

Planner and 3D pixel sensors with an active thickness of 150 um and pixel sizes of 25 \times 100 um^2 or 50 \times 50 um^2 have been produced by Hamamatsu Photonics (HPK), Fondazione Bruno Kessler (FBK), and Microelectronic National Center(CNM). The sensors were bumped bonded to the RD53A readout chip prototype. The sensor-chip modules were irradiated with 23 MeV and 24 GeV protons to the fluence of up to 2.4 \times 10^16 cm^-2 the Karlsruhe Institute of Technology (KIT) and PS-IRRAD proton facility.

The modules were tested in the DESY II beam test facility. The hit efficiency and spatial resolution as a function of the incidence angle of pixel sensors were determined from these measurements. It has been shown that for the highest fluence, the planar modules still reach 99\% hit efficiency, required for the Phase-2 IT, at bias voltages below 800V. For 3D sensors, no significant change in efficiency was observed after irradiation. This talk presents the results for planar and 3D sensors before and after irradiation.

Speaker: Mohammadtaghi Hajheidari (Hamburg University (DE))

PSD12_2nd.pdf

47 LHCb VELO upgrade

The Vertex Locator (VELO), surrounding the interaction region of the LHCb experiment, reconstructs the collision points (primary vertices) and decay vertices of long-lived particles (secondary vertices). The upgraded VELO will be composed of 52 modules placed along the beam axis divided into two retractable halves. The modules will each be equipped with 4 silicon hybrid pixel tiles, each read out with by 3 VeloPix ASICs, glued onto a thin silicon plate with embedded micro-channels that allow the circulation of liquid CO$_2$. The silicon sensors must withstand an integrated fluence of up to 8$\times 10^{15}$ 1 MeV n$_{eq}$/cm$^{2}$, a roughly equivalent dose of 400 MRad. The highest occupancy ASICs will have pixel hit rates of 900 Mhit/s and produce an output data rate of over 15 Gbit/s.

The design of the VELO upgrade will be presented with the results from the latest R\&D and detector construction.

Speaker: Kazuyoshi Carvalho Akiba (Nikhef)

PSD LHCb VELO upgrade 15th September.pdf

48 ALICE ITS3: the first truly cylindrical inner tracker

The high integration density of Monolithic Active Pixel Sensors (MAPS), with silicon sensor and readout electronics implemented in the same device, allows very thin structures with strongly reduced material budget. Thicknesses of O(50um), values at which silicon chips become flexible, are readily used in many applications. In addition, MAPS can be produced in sensors of wafer size by a process known as stitching. This in turn allows to build detector elements that are large enough to cover full tracker half-layers with single bent sensors.

The ALICE ITS3 project is planning to build a new vertex tracker based on truly cylindrical wafer-scale sensors, with <0.05% X0 per layer and as close as 18 mm to the interaction point. R&D on all project aspects (incl. mechanics for bent wafer-scale devices, test beams of bent MAPS, design of stitched sensors) is rapidly progressing with the aim for installation during LHC LS3.

This contribution will summarise the project motivation, its R&D schedule, and will show selected highlights of recently accomplished project milestones, including full-scale engineering prototypes with dummy chips and small-scale, fully functional assemblies of functional, bent MAPS.

Speakers: Magnus Mager (CERN), Domenico Colella (Politecnico and INFN Bari, Italy)

PSD12_Colella_ITS3.pdf

49 Latest developments and characterisation results of the MALTA sensors in TowerJazz 180nm for High Luminosity LHC

MALTA is a novel monolithic active pixel CMOS sensor chip designed in TowerJazz 180nm imaging technology which targets radiation hard applications for the HL-LHC and beyond. Several process modifications and front-end improvements have been investigated and have resulted in radiation hardness up to 2e15 n/cm2 with time resolution below 2 ns. Further improvements to detector efficiency have been explored by changing the starting material for these sensors and using Czochralski instead of epitaxial silicon. This contribution will present the results from latest submission from the extensive lab testing and the characterization in particle beam tests with special focus on the new MALTA2 sensor.

Speaker: Andrea Gabrielli (CERN)

andreagabrielli_PSD12.pdf

10:20 Coffee/Tea

Posters Session 1 (Applications in Astro-particle Physics; Applications in Astronomy, Planetary and Space Science; Applications in Life Sciences and Biology)

Applications in Astro-particle Physics
Applications in Astronomy, Planetary and Space Science
Applications in Life Sciences and Biology

Conveners: Tony Price (University of Birmingham (GB)), Laura Gonella (University of Birmingham (UK))

50 Extensive Air Shower Tracker using Cherenkov Detection

Cosmic rays continuously bombard Earth’s atmosphere triggering cascades of secondary particles. Many constituents progress to reach the surface and capturing these events can intrigue and awe young curious minds, opening them to the amazing world of physics. Cloud chambers are an established method of revealing the subatomic world; frequently used by universities to introduce cosmic rays to visitors and prospective students. Although their scientific use is limited, they provide a fascinating real-time display of the ‘ghostly’ particles showering upon those viewing.
Using the Cherenkov radiation detection technique, we have developed a novel, compact, Extensive Air Shower (EAS) particle tracking method that enhances the cloud chamber visualisation of cosmic ray interactions towards a digital audience. Once digital, live event interaction can be streamed to multiple display devices presenting an immediate illustration of the event that showered in that location.
Our instrument hardware is built around Cherenkov optimised silicon photomultiplier sensors. Each single detection unit is able to monitor particle event rate, track incident angle and measure Cherenkov intensity, thereby enabling energy discrimination between low versus high-energy interactions. By operating multiple detection units in one location, we can record time correlated air shower events to monitor and generate information on primary cosmic rays.
We introduce first results, illustrating instrument response and EAS rate variations, compiled from the initial six month running period of our development instruments. We also present instrument simulations to assess and optimise the number and position of our photosensors.
With further development towards low-cost readout electronics, we aim to build a networked array of trackers, located around the campus, to expand data gathering ability and scientific potential. By tracking EAS in real-time we can estimate the local distribution of secondary particles, allow us to determine particle radiation levels, and provide atmospheric radiation monitoring locally, regionally and potentially UK-wide.

Speaker: Dr Steven Leach (University of Leicester)

PSD12_LEACH_EAS Tracking_130921.pdf

51 An introduction to DAMIC-M experiment

The DAMIC-M project is devoted to the exploration of the hidden sector and the search for light Dark Matter particles using Charge-Coupled Devices (CCDs). It follows the DAMIC at SNOLAB experiment which pioneered the detection of new particles through their interaction with the nucleus or the electrons of the bulk silicon of fully depleted CCDs.. A kilogram-sized target mass will be installed at the Modane underground laboratory (LSM, France) which offers an excellent low background environment for rare-event search. DAMIC-M detectors demonstrate several technological advancements including the implementation of the skipper technique, and custom front-end control and read-out electronics. Skipper CCDs can perform multiple non-destructive measurements of the pixel charge that allow for a read-out noise of a fraction of an electron. With a 15μm x 15μm pixel area, 675µm thickness and the ability of 3D reconstruction using the diffusion of the particle track, the spatial resolution of our CCDs allows for the follow-up of radioactive chains, a powerful tool to discriminate genuine particle interaction from in situ radioactive decays. Together with an extremely careful fabrication procedure that controls the contaminant and the generation of bulk radioactive contamination by cosmic ray spallation, the single electron resolution will guarantee a detection energy threshold of only a few eVs, pushing the sensitivity of DAMIC-M by at least one order of magnitude better than previous experiments. I will present the current status of DAMIC-M describing our technological challenges and the solutions we have adopted. I will introduce our method to measure and mitigate the bulk radioactive contamination and discuss the ongoing assembly of a prototype detector (the Low Background Chamber) aiming at validating our design options.

Speaker: Georgios PAPADOPOULOS (DAMIC)

Georgios_Papadopoulos_PSD12_poster.pdf

52 Single-Photon Avalanche Diode detector for Raman spectroscopy with time-gated fluorescence suppression.

Single-photon avalanche diode (SPAD) detectors are revolutionising modern imaging and spectroscopy thanks to detection capabilities at the level of individual photons and ultrafast response times. Very recently, time-gated cameras based on SPAD technology have been proposed for improving the performance and applicability of Raman spectrometers through addressing the suppression of fluorescence interference in the most commonly used, near infrared spectral region – one of the greatest, largely unmet, challenges in modern Raman spectroscopy. The effectiveness of existing solutions is at present restricted to a small subset of samples and regimes of operations due to their poor near-infrared (>800 nm) sensitivities, low frame rates and small 1D array formats.

To deliver a step-change in Raman detection capabilities, we propose the development of a SPAD sensor chip having near-infrared enhanced sensitivity (optimised for 750-950 nm), larger format (architecture scalable up to 1000x250 pixels) and timing resolution on the order of a few hundred picoseconds. The chip which will combine SPAD devices with an on-chip Delay Locked Loop (for timing accuracy), advanced counting architecture (for high light level applications) and a high speed readout (for high frame rates up to 40 Mfps). The design of the chip has been completed and submitted for fabrication in a 180 nm CMOS Image Sensor process. In this paper, we present the architecture of the device and discuss plans for future testing.

Speaker: Herman Larsen (Science and Technology Facilities Council)

IRIS_PSD12_poster_Herman_Larsen.pdf

53 TRISTAN: A novel detector for searching keV-sterile neutrinos at the KATRIN experiment

The KATRIN (Karlsruhe Tritium Neutrino) experiment investigates the kinematic endpoint of the tritium $\beta$-decay spectrum to determine the effective mass of the electron anti-neutrino. The collaboration reported its first neutrino mass result in fall 2019: $m_ν<1.1~ \rm{eV} $ (90% CL). Its unprecedented tritium source luminosity and spectroscopic quality make it a unique instrument to also search for physics beyond the standard model such as sterile neutrinos.

Therefore, we develop a new detector for the KATRIN experiment to detect the signature of a sterile neutrino in the keV mass regime. In order to obtain a high sensitivity to the sterile neutrino mixing angle, excellent spectroscopic properties at high rates are essential. The novel TRISTAN detector system will exploit the silicon drift detector technology, which meets these requirements due to its small anode capacitance of less than $200~\rm{fF}$, and scale this technology to a large array of more than 3000 pixels.

This poster will present the design and status of the new detector, where we recently reached an important milestone by operating one 47-pixel detector module. A special focus will be put on the characterization of inter-pixel effects, which play an important role in the highly integrated multi-pixel detector system.

Speaker: Korbinian Urban (Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München, Germany; Physik-Department, Technische Universität München, D-85747 Garching, Germany)

poster_dsp12_kurban_tristan.pdf

54 Dynamic Imaging of moving radiotracers using combined PET and Compton camera system with scintillation pixel detectors

Monitoring and imaging the moving radioisotope are required in several clinical situations, such as the tracer injection and its leakage monitoring in PET scan procedure. We have designed and developed a combined Compton camera and PET coincidence system to monitor the moving radioisotope using 3 mm pixel 8 x 8 GAGG scintillation crystal arrays coupled to SiPM arrays with time-over-threshold (ToT) based individual readout circuits and its dynamic imaging performance is compared. The measured resolution of PET and Compton camera is 3.2 mm and approximately 14 degrees for 22Na point source respectively. The radiotracers with the activity from 12.5 MBq to 100 MBq moving with the speed of 1 mm/s to 10 mm/s mimicking the blood flow are used in the experiment. In PET coincidence imaging, images are successfully visualized for all the activities with the resolution of 5.5 mm to 7.8 mm. In Compton imaging, images are correctly reconstructed only with the activity less than 25 MBq with the resolution of 20 mm because of the random coincidence events. PET showed better tracking capability of activity and speed of radiotracers up to 100 MBq. On the other hand, Compton imaging has wider field-of-view to monitor the large area compared with the limited FOV in PET system. The detail detector performance and imaging results will be shown in the conference.

Speaker: Kenji Shimazoe (The University of Tokyo)

55 Modelling CTI effects in irradiated Gaia CCDs

The European Space Agency’s Gaia spacecraft was launched in 2013 and has been in operation ever since. It has a focal plane of 106 Charge-Coupled Devices (CCDs) which are of the CCD91-72 variant, custom-designed by Teledyne e2v. The detectors have been making measurements of parallaxes, positions, velocities, and other physical properties of over one billion stars and other astronomical objects in the Milky Way. Whilst operating in space, CCDs undergo non-ionizing displacement damage from incoming radiation. This causes radiation induced defects to form in the silicon lattice which can trap electrons during readout and increase the charge transfer inefficiency (CTI) of the devices. From analysis of in-flight calibration data, Gaia’s CTI values have been measured to be much lower than what was expected based on the on-ground pre-flight tests.

In this study, the CTI and trap landscape in both in-flight and irradiated on-ground devices are modelled to fit the new datasets. These results provide more insights into the nature of radiation damage and the resulting trap landscapes, both in space and from on-ground irradiations.

Speaker: Saad Ahmed

56 Picosecond imaging at high spatial resolution using TOFPET2 AISC v2d and Microchannel plate detectors

Microchannel plate-based detectors provide advantages over their solid-state counterparts for applications where a combination of virtually zero noise photon-counting, large format, short wavelength sensitivity with high resolution timing and imaging are required. Solar-blind applications, Cherenkov detectors for high energy physics, and UV astronomy are such fields. The application to Cherenkov detection is particularly demanding, requiring time resolution below 100 picoseconds combined with imaging and high throughput. This requires the readout to combine high spatial and temporal event resolution at high rates necessitating a parallel readout approach. We describe a readout design comprising a pixellated readout array instrumented using multi-channel fast timing electronics and incorporating charge centroiding to achieve sub-pixel spatial resolution. We present experimental results of the relationship between time over threshold and signal amplitude, the centroiding image obtained with an MCP detector using a pixellated readout geometry. The readout was optimised for a fast electronics implementation based on the TOFPET system, a multi-channel all-in-one ASIC originally designed for time-of-flight PET using silicon photomultipliers.

Speaker: Thawatchai Sudjai (University of Leicester)

Thawatchai_Sudjai_ID171.pdf

Applications in Astro-particle Physics; Applications in Astronomy, Planetary and Space Science 2

Conveners: Martin Freer (University of Birmingham), Philip Patrick Allport (University of Birmingham (UK))

57 Applications of Astro-particle Physics Position Sensitive Detectors

Speaker: Robert Johnson (Santa Cruz Institute for Particle Physics (SCIPP))

RJohnson.pdf

58 Charge-to-light signal conversion in liquid xenon for future TPC detectors

Proportional scintillation of electrons in liquid noble gases is a promising signal amplification mechanism for future time projection chamber experiments (TPC) with liquid xenon targets. The detection of the charge signal in state-of-the-art multi-tonne dark matter experiments, like XENONnT or LZ, relies on the extraction of the electrons into a thin gas phase where proportional scintillation occurs in electrical fields of O(10$\,$kV/cm). In our approach, scintillation photons are produced in liquid xenon within a few $\mathrm{\mu}$m of thin wires, where electrical fields of O(500$\,$kV/cm) can easily be obtained.
Omitting the gas phase overcomes technical challenges limiting the performance of large detectors and allows alternative design approaches with potentially increased science reach.
We discuss the paradigm change in charge signal reconstruction using this amplification method with respect to the traditional dual phase scheme. Exemplary aspects with significantly improved detector performance will be shown.
Furthermore, we report on experimental measurements showcasing position sensitive event reconstruction capability in a small scale R&D detector.

Speaker: Fabian Kuger (Albert-Ludwigs-Universität Freiburg)

2021_09_SinglePhase_PSD12.pdf

59 Towards the first observation of the Migdal effect in nuclear scattering I. Design and construction of the MIGDAL experiment (in-person)

The Migdal in Galactic Dark Matter Exploration (MIGDAL) experiment aims at making the first observation of the Migdal effect from fast neutron scattering. A Migdal event can be identified by two ionization tracks sharing the same vertex, one belonging to a nuclear recoil and the other to a Migdal electron. To detect this track topology in a low-pressure gas we are building an Optical Time Projection Chamber equipped with glass-GEMs operating in 50-Torr CF4, with light and change readout provided by a CMOS camera, a photomultiplier tube, and 120 anode-strip channels. This will allow precise three-dimensional reconstruction of the ionization tracks from electron and nuclear recoils down to 5 keV in electron equivalent energy. The detector will be exposed to intense neutron beams (109-1010 n/s) from DT and DD neutron generators, enabling us to investigate the Migdal effect in a wide energy range of nuclear recoils. We will report on the status of the design and construction of the experiment at the Neutron Irradiation Laboratory for Electronics (NILE) of the Rutherford Appleton Laboratory, UK.

Speakers: Mohammad Nakhostin (Imperial College London), Tom Neep (University of Birmingham (GB))

Mohammed Nakhostin.pdf

60 Directional Dark Matter Search with NEWSdm

In spite of the extensive search for the detection of the dark matter (DM), experiments have so far yielded null results: they are probing lower and lower cross-section values and are touching the so-called neutrino floor. A way to possibly overcome the limitation of the neutrino floor is a directional sensitive approach: one of the most promising techniques for directional detection is nuclear emulsion technology with nanometric resolution. Nano Imaging Trackers (NIT) is the last generation of nuclear emulsions, designed on purpose for a directional DM search. It has an extremely high granularity, and it required the development of fast super-resolution imaging technique for its readout. The NEWSdm experiment, located in the Gran Sasso underground laboratory in Italy, uses the NIT emulsion acting both as the Weakly Interactive Massive Particle (WIMP) target and as the nanometric-accuracy tracking device. This would provide a powerful method of confirming the Galactic origin of the dark matter, thanks to the cutting-edge technology developed to readout sub-nanometric trajectories. In this talk we discuss the newly-developed super-resolution readout technique, the NEWSdm experiment design, its physics potential, the performance achieved in test beam measurements and the near-future plans.

Speakers: Andrey Alexandrov (Universita e sezione INFN di Napoli (IT)), Andrey Alexandrov (INFN sez. di Napoli)

Alexandrov_PSD12.pdf

Alexandrov_PSD12.pdf

Alexandrov_PSD12.pptx

61 The CMOS pixel sensors particle tracker for the CSES-02 space experiment

The CSES (China Seismo-Electromagnetic Satellite) mission will put into orbit satellites to study perturbations in the ionosphere, possibly correlated with the occurrence of seismic events. The first satellite is successfully operated since 2018, and the launch of the second is scheduled for the end of 2022. CSES-02 will be supplied with a High-Energy Particle Detector (HEPD), designed for the detection of electrons (protons) in the 3-150 (30-250) MeV energy range.
Its tracker is based on the innovative monolithic pixel sensors ALPIDE, developed for the ALICE experiment, at CERN. This technology has never been used in the space environment. This talk will describe the spatialisation process carried out by the HEPD-02 tracker team, which has adapted the operation mode of the ALPIDE sensor to build a modular and compact particle detector. The tracker is made of 5 turrets, each one containing 3 stacked sensitive planes. All of 150 ALPIDE sensors are interconnected with wire bonds to Flex Printed Circuits, used to transmit power, control, and readout data. The mechanical support consists of Carbon Fiber Reinforced Plastics structures, to which the chips are glued. We describe in detail the HEPD-02 tracker project, demonstrating the possibility of using MAPS in space and manifesting the pioneering nature of the project for next-future larger size space missions.

Speaker: Stefania Beole (Universita e INFN Torino (IT))

Beole_PSD12_v0.pdf

12:50 Lunch

Poster Session 2 (X-ray and Gamma Ray Detectors; Applications in Nuclear Physics and Nuclear Industry; Detectors for FELS, Synchrotrons and Other Advanced Light Sources; Detectors for Neutron Facilities; Novel Ionising Radiation Detection Systems)

X-ray and Gamma Ray Detectors
Applications in Nuclear Physics and Nuclear Industry
Detectors for FELS, Synchrotrons and Other Advanced Light Sources
Detectors for Neutron Facilities
Novel Ionising Radiation Detection Systems

Conveners: Martin Freer (University of Birmingham), Tony Price (University of Birmingham (GB))

62 “RIPTIDE” – An innovative recoil-proton track imaging detector

Neutron detectors perform key tasks in the development of many research fields, as nuclear, particle and astroparticle physics as well as neutron dosimetry, radiotherapy, and radiation protection. Until now, no neutron detector exhibits tracking capability (i.e., full neutron-momentum reconstruction) even if several projects are in progress [1-7]. To address this deficiency, we aim at developing a novel RecoIl-Proton Track Imaging DEtection system “RIPTIDE”, in which the light output of a fast scintillation signal is used to perform a complete reconstruction in space and time of the neutron-proton elastic scattering. Preliminary Geant4 simulations of the proposed set-up show up a good detection efficiency in a compact active volume. In addition, the proposed electronic readout can be easily adapted according to a specific application (event-by-event mode or integration mode). In principle, the system can be also rescaled by increasing the detection volume or by combining several detection modules. Finally, further development of the basic detection technique can be adapted for fast charged particle detection tracking.
In this contribution, we will present the RIPTIDE concept together with some preliminary results.
[1] J. Hu, J. Liu, Z. Zhang, et al., Sci. Rep. 8, 13363(2018);
DOI:10.1038/s41598-018-31711-z
[2] S.M. Valle, et al., NIM A 845(2017)556;
DOI:10.1016/j.nima.2016.05.001
[3] E.Gioscio, et al., NIM A 958(2020)162862;
DOI:10.1016/j.nima.2019.162862
[4] G. Wang,L. Zhang,W. Song, et al., J. Appl Spec. 87(2020)911; DOI:10.1007/s10812-020-01088-x
[5] M. Marafini, et al., Phys. Med. Biol. 62(2017)3299;
DOI:10.1088/1361-6560/aa623a
[6] R. Combe, et al., EPJ Web Conf. 170(2018)09001; DOI:10.1051/epjconf/201817009001
[7] T.J. Langford, et al., JINST 11(2016)P01006;
DOI:10.1088/1748-0221/11/01/P01006

Speaker: Prof. Agatino Musumarra (University of Catania, Dipartimento di Fisica e Astronomia and INFN sezione di Catania)

63 Simulations of charge collection of a gallium-nitride-based pin thin-film neutron detector

The development of new fast neutron reactors and nuclear fusion reactors requires new neutron detectors in extreme environments. Due to its wide bandgap (3.4 eV) and radiation resistance capability, gallium nitride (GaN) is a candidate for neutron detection in extreme environments. In this study, a GaN-based pin thin-film thermal neutron detector with lithium fluoride (LiF) converter layer is modelled by Geant4. After obtaining the neutron energy deposition distribution in the sensitive volume of the detector, the Hecht equation is used to calculate the charge collection efficiency at different position of the detector under a uniform electric field. In addition, considering charge recombination processes, the Shockley-Ramo theorem is applied to obtain more accurate simulation results. The result of the charge collection simulations is used to study its influence on the californium-252 ($^{252}$Cf) energy spectrum measurement of the detector.

Speaker: Zhongming Zhang (Lancaster University)

Zhognming Zhang, PSD12.pdf

64 AGIPD systems for the European XFEL, development and upgrades.

The European XFEL is one of the newest X-ray facilities in the world with a very demanding requirements for the detectors operating at the experimental stations and recording high quality scientific data. Those requirements include high dynamic range from single up to 10⁴ 12.5 keV-photons. The accelerator operates with a very specific time structure producing bunch trains of 2700 pulses at 4.5 MHz repetition rate. The trains are repeated with an infra-frequency of 10 Hz. These key features enable the conduction of modern physical experiments and at the same time put challenging requirements on the detectors.
The AGIPD (Adaptive Gain Integrating Pixel Detector) developed for the European XFEL is based on hybrid pixel technology using direct photon conversion in a semiconductor sensor bump-bonded to the front-end microelectronics. Each pixel of the AGIPD ASIC uses a charge-sensitive preamplifier with adaptive gain and 352 random-access memory cells in order to record as many images as possible from the bunch train, and transfer them to the back-end electronics between the bursts. The data is then transferred to the acquisition system via 16 10Gbit optical links. The detector is running in vacuum and also subject to considerable radiation dose.
The first 1-megapixel system was delivered to the SPB instrument in summer 2017 and started operation already in September 2017. The second 1-megapixel was used for first experiments at the MID instrument in the early 2019. Two 2nd generation systems (4 and 1 megapixels) are to be delivered to SFX and HED instruments, utilizing modern back-end electronics and the latest version (1.2) of the AGIPD ASIC. Efforts on enhancement of the front-end hybrid production yield, upgrades of the 1st generation systems and the status of newer developments for AGIPD will be presented.

Speaker: Alexander Klyuev (Deutsches Elektronen-Synchrotron)

psd12_klujev_#62.pdf

65 Tristan10M detector: Characterization of a large area detector for time resolved experiments based on Timepix3 chip

Tristan10M is a 10 million pixel area detector based on the Timepix3 chip, a member of the Medipix family of ASICs for X-ray and particle imaging and detection developed by the Medipix collaboration led by CERN. The Timepix3 ASIC can work in event driven mode in addition to the standard frame based mode. Event driven mode enables the chip to send out a data packet containing the pixel coordinate, time over threshold and time of arrival immediately after each hit is processed by a pixel. Thanks to these capabilities of the Timepix3 ASIC, the Tristan detector is ideal for time-resolved experiments. The Tristan 10M detector is organized in a 5 x 2 module matrix, each module being made up of sixteen Timepix3 chips bump-bonded to a monolithic pixelated silicon sensor. In this contribution, we will report on the status of the detector development, and characterization results in terms of threshold equalization, energy calibration, and flat-field correction. A number of initial commissioning experiments have been carried out on the small molecule single crystal diffraction beamline I19 at Diamond light source, which we will also report on here. In particular, X-ray powder diffraction from a standard sample, LaB6, was performed to evaluate the inter-module alignment in six degrees of freedom and to produce a correction matrix suitable for application to future experimental data.

Speaker: Mr Zongde CHEN (diamond light source)

PSD12_poster_Zongde_CHEN.pdf

66 A programmable readout system for 3He/BF3 neutron detectors

Neutron sources are currently becoming a standard to investigate the structures of various materials at mesoscopic scale using elastic scattering techniques, which are applied across a wide spectrum of scientific disciplines such as physics, biology, materials science. Moreover, having the capability of detecting neutrons is a common request of Radioprotection and Security fields, especially in those applications where you need to locate a potentially hazardous neutron emitter, measure its energy and reconstruct its position.
Typical neutron physics experiments carried out at Neutron Spallation Sources and other laboratories (like ESS, SNS, CSNS, ISIS, ILL, …) make use of large arrays of 3He/BF3 position-sensitive tubes to detect neutrons. On the other hand, Nuclear Security main players need more compact systems with standalone electronics to bias and read out neutron detectors.
CAEN SpA has developed a 19” rack-mount solution for the readout of 3He/BF3 tubes, which can be tailored for both above mentioned scenario, including neutron physics experiments and environmental/security monitoring system. It is a scalable system allowing to put together few to hundreds neutron detectors. It can be composed starting from three basic building blocks: R803x High Voltage board, R1443 Charge Sensitive Preamplifier specifically designed for 3He/BF3 tubes and R5560 14-bit 125MS/s open FPGA Digitizer. Thanks to its firmware programmability, this readout system can perform specific filtering to achieve the best charge, timing and position measurements.
CAEN provides a DAQ software to remotely manage the system and acquire waveforms, energy, ToF spectra and perform position reconstruction. Moreover, the R5560 offers the possibility to use SCI-Compiler, a block-diagram-based software which allows to easily implement custom pulse processing algorithms in the board FPGA.

Speaker: Mr Yuri Venturini (CAEN SpA)

poster_YuriVenturini_CAEN.pdf

67 A hybrid pixel detector with 4D information for dynamic synchrotron radiation applications

In this paper, a new concept of detector is proposed for dynamic synchrotron radiation applications. It is based on the conventional hybrid pixel detector architecture, while the readout chip is designed with hit-driven readout scheme rather than frame refreshing. Based on ToT (Time over Threshold) structure, each pixel can acquire 4D information, including 2D position, timing, and energy of every incoming photon. This not only enhances the detector timing performance to several tens of nanosecond compared to the typical millisecond by photon counting, but also enables the possibility of wide-band X-ray imaging while typical synchrotron radiation experiments usually only deal with monochrome energy.
The pixel readout chip, TETPIX, was designed using a CMOS 130nm technology and taped out with a full mask engineering run. It integrates a 64×32 pixel array with a pixel size of 150μm×150μm. The readout scheme is based on a “column-drain” architecture, that simultaneous incoming hits in every column will be sequentially readout controlled by a priority arbitrary logic in the pixel. The time stamps of both edges of ToT pulses will be latched in pixel registers, where the leading edge corresponds to the hit time and the difference between the both edges represents the energy. Data are readout by a high speed serializer off chip.
A sensor measures 1.92cm×1.92 cm was bump bonded with 2×2 readout chips, and the module was then wire bonded to a readout PCB. Preliminary test results on BSRF (Beijing Synchrotron Radiation Facility) showed that the module can achieve a energy resolution better than 20% in the full range of BSRF from 8keV to 16keV, and the timing performance was about 20ns with 50MHz clock frequency. With this capability, the fine architecture of the bunch crossing of the accelerator can clearly be seen. Other experiment results are also discussed in this paper.

Speaker: Wei Wei (IHEP, CAS, China)

A hybrid pixel detector with 4D information for dynamic synchrotron radiation applications.pdf

68 HEPS-BPIX4: A Prototype Pixel Readout Chip Working in Single Photon Counting Mode with a Novel Charge Sharing Suppression Scheme

HEPS-BPIX4 is a hybrid pixel detector readout chip for X-ray applications for the High Energy Photon Source (HEPS) in China. The prototype readout chip contains an array of 20 × 32 pixels with a pixel size of 55 μm × 55 μm, working in single photon counting mode. Each pixel handles with both positive and negative input charge signals and has a counting depth of 11 bits. The chip could work at a 160 Mbps output data rate with zero dead time.
Besides the chip design description, this paper also proposes a novel architecture aiming at eliminating the spectral distortion caused by the charge sharing effect due to the fine pixel pitch. It is based on charge summing and centroid arbitration among adjacent pixels. In every cluster grouped by 3×3 pixels in the chip, charge deposited in four pixels by a single photon is concentrated into the center pixel and added together. Then it is compared with the energy threshold for discrimination. In the meantime, the center pixel is also judged by a secondary comparator with a minimum threshold. Then the arbitrator decides if the charge of the center pixel is the maximum. Only those two matched conditions give a photon counting pulse to the digital part.
Compared with reported schemes that transmitted more than ten signals, the proposed scheme reduced the complexity of communicated pixels interconnection in the layout. There are only seven signals including three analog signals and four digital signals received by the center pixel from the adjacent four pixels. Besides, it improved the charge sharing decision precision to be as high as 99% and has been verified by python modelization simulation. The chip has been manufactured and tested. Detailed results, especially the charge sharing cancellation test in the pixel array, is given in this paper.

Speaker: Shanshan Cui

PSD_POSTER_ShanshanCUI_HEPS-BPIX4.pdf

69 Online control of the gain drift with temperature of SiPM arrays used for the readout of LaBr3:Ce crystals

LaBr3:Ce crystals have been introduced for radiation imaging in medical physics, with photomultiplier or single SiPM readout.
An R&D was pursued with 1/2" and 1" LaBr3:Ce, from different producers, to realize
compact large area detectors (up to some cm2 area) with SiPM array readout, aiming at high light yields, good energy resolution, good detector linearity and fast time response for low-energy X-rays. A natural application was found inside the FAMU project at RIKEN-RAL muon facility, that aims at a precise measure of the proton Zemach radius to solve the so-called "proton radius puzzle", triggered by the recent measure of the proton charge radius at PSI. The goal is the detection of characteristic X-rays around 130 KeV. Other applications may be foreseen in medical physics, such as PET, and gamma-ray astronomy. A limiting factor is the gain drift of SiPM arrays with temperature, that may give a major deterioration of the FWHM detector's energy resolution. To solve this problem a custom NIM module was developed, based on CAEN A7585D digital power supplies, with temperature feedback. Up to eight channels may be powered by a single 2-slots NIM module. The control of this module was implemented via either a FDTI USB-I2C converter or an Arduino Nano chip. Three modules (with which up to 24 channels may be powered) were realized and are linkable in daisy chain, via the I2C protocol. Test results of the correction of gain drift with temperature for SiPM arrays from Advansid, Sensl, Hamamatsu will be presented, together with the ones obtained on energy resolution, detector linearity, ... for the realized LaBr3:Ce detectors.
As an example, at the Cs137 peak, an energy resolution better than 3 % was obtained, using Hamamatsu S13461 arrays , that compares well with best available results obtained with a PMTs.
~

Speaker: Maurizio Bonesini (Universita & INFN, Milano-Bicocca (IT))

poster_PSD12.pdf

70 Evaluation of the performance of the CCD236 Swept Charge Devices in lunar orbit using in-flight data.

India’s Chandrayaan-2 Large Area Soft X-ray Spectrometer (CLASS), launched in 2019 aboard the Chandrayaan-2 spacecraft, has now spent an extended period of time in lunar orbit. CLASS is currently mapping the elemental composition of the lunar surface using X-ray spectrometry.

Building on the heritage of earlier instruments, CLASS employs 16 CCD236 Swept Charge Devices (SCDs) similar in structure to Charge Coupled Device (CCD) image sensors. The CCD236 permits X-ray detection over a large surface area, intended to improve low flux performance, with simplified control interfaces and reduced temperature requirements. These devices were the subject of ground testing and performance evaluation before flight. Data recently made available by the Indian Space Research Organisation (ISRO) has permitted the analysis of the performance of the CLASS SCDs after over a year of operations around the Moon. Of particular interest is the change in device performance and behaviour during transit and in lunar orbit. Preliminary analysis has indicated that the instrument FWHM, representing the aggregate response of most devices, has increased less than predicted by ground irradiation.

The authors will present the latest results from the analysis of instrument data with comparisons to earlier work completed on similar devices.

Speaker: Lawrence Jones (The Open University)

L_Jones_Poster_PSD12_item_103.pdf

71 Measurement of angular correlations in positronium decay using GaGG scintillator matrices with single-side readout by silicon photo-multipliers

Gamma-ray polarization is of prime interest in many areas of physics. One particular is biomedical imaging with positron emission tomography (PET). Two orthogonally polarized, entangled gamma-rays are emitted in an event of para-positronium annihilation thus they are strongly correlated. When they undergo Compton scattering, the initial correlation dominantly results in their orthogonal azimuthal scattering. This correlation can be used in PET as an additional criterium for distinguishing a true coincidence event from the background where such correlation is lacking. In a previous study we showed a moderate azimuthal correlation could be observed via Compton scattering in system of two 4x4 Lutetium Fine Silicate (LFS) scintillation matrices. The goal of the present study is to increase the detector sensitivity to azimuthal correlation, where one of the important parameters is the energy resolution. Hence, we measured azimuthal correlations of annihilation quanta with two 8x8 matrices of Gadolinium Aluminum Gallium Garnet doped with Cerium (GaGG:Ce). Each detector matrix contains 64 crystals of size 3 mm x 3 mm x 20 mm and it is read-out by a single Silicon Photo-multiplier (SiPM) array, with one SiPM matching one pixel. The studied single-side readout concept keeps the modules compact and cost-efficient on a large scale. Coincidence events were recorded using a Na-22 source placed between the modules and the mean energy resolution at 511 keV was 9.7% ± 0.5% and 11.3% ± 0.7% for the two modules, respectively. We clearly identified and reconstructed the Compton scattering events and we observe the excess of orthogonally scattered gammas over the ones with the parallel azimuthal angles. We present the measured azimuthal modulation factors for several kinematic selection criteria and different inter-pixel distances and we compare them to previous findings with 4x4 LFS scintillators. Finally, we discuss the perspective of using the presented concept in PET.

Speaker: Siddharth Parashari

Siddharth_Poster_ID#106_PSD12.pdf

72 Flexible X-Ray Imaging Detectors Using Scintillating Fibers

We will present designs and simulations of a novel X-ray imaging detector. The intent of the FleX-RAY project is to create a digital X-ray detector that is capable of producing high-resolution images, is flexible enough to produce an image on a curved surface, and is capable of self-reporting its final shape.

The X-rays will be detected on a sheet of scintillating optical fibers, which will guide the scintillation light to single-photon avalanche photodiodes. This setup allows the electronics and hardware to be moved out of the path of the X-ray beam, limiting the need for additional shielding. Self-shape-reporting will be achieved using a flexible ultra-thin glass foil substrate with optical waveguides and Bragg gratings, processed by femtosecond laser point-by-point writing. The functionalized glass substrate allows precise measurement of strains, which can be used to calculate the shape.

This presentation will describe the results of simulations of the detector using a range of materials, geometries, and X-ray sources. By modifying these parameters, we can optimize the detector for various applications.

Speaker: Scott Wilbur (University of Sheffield (GB))

poster_tikz.pdf

73 The Hyperbolic drift chamber for ALERT

A Low Energy Recoil Tracker (ALERT) experiment will occur in Hall B at Jefferson Laboratory, Virginia, USA. It will study the partonic structure of bound nucleons in He-4. The ALERT detector must track and identify low energy nucleons and light nuclei of momenta ranging from 70 MeV/c to 250 MeV/c at a rate up to 60 MHz. It will be used in tandem with the already installed CLAS12 spectrometer in Hall B to detect the scattered electrons.
ALERT is composed of a tracker and a time of flight detector (TOF). The tracker is designed to minimize the amount of material before the particles reach the TOF. This talk will present the ALERT Hyperbolic Drift Chamber developed for the tracker. It will detail the readout, mechanical and mounting challenges posed by the wire density of 24 wires/cm2. It will be followed by the resolutions expectations compared to the performance of prototype obtained during beam tests performed at a accelerator facility (ALTO) in Orsay, France.

Speaker: Gabriel Charles (Université Paris-Saclay (FR))

PSD12.pdf

74 Automatic detection of scintillation light splashes using conventional and deep learning methods

The Hybrid Gamma Camera (HGC) [Lees et al, Sensors, 17(3):554, 2017] has applications in intraoperative imaging guidance and nuclear decommissioning. The HGC gamma detector comprises an Electron Multiplying Charge-Coupled Device (EMCCD) coupled to a columnar CsI: Tl scintillator. Each absorbed gamma photon will produce a scintillation light splash on the EMCCD; the number, location, and size of these splashes on each frame is unknown. For real-time imaging, these splashes must be identified and characterised quickly (10fps) and with minimal processing overhead. The current technique used in the HGC is automatic scale selection [Hall et al, NIMA,604:207-210, 2009]. However, there alternative solutions including object recognition deep learning models may have superior performance.
Six automatic detection implementations - four traditional blob detection algorithms (two Laplacian of Gaussian (LoG) detectors: LoG(1) is our implementation of LoG algorithm based on the HGC’s automatic scale selection and LoG(2) is the LoG detector from Python scikit-image library, one Difference of Gaussian (DoG) detector, and one Hessian of Determinant (DoH) detector) and two Region-Based Convolutional Neural Networks (RCNNs) based on the VGG16 and ResNet-101 models were compared for the task of scintillation light splash identification.
An image dataset was simulated based on statistics of experimental data from the HGC for a range of radioisotopes. This provided ground truth values for location, intensity, and size of expected splashes for training RCNN models. The testing performance of each technique was compared based on results from 360 simulated images. The F1-scores obtained were: LoG(1): 69.98%, LoG(2): 98.85%, DoG: 94.03%, DoH: 32.05%, VGG16: 90.37% and ResNet-101: 89.95% . Their average speed for per frame was LoG(1): 0.358s/f, LoG(2): 0.024s/f, DoG:0.021s/f, DoH: 0.069s/f, VGG16: 0.057s/f, ResNet-101: 0.072s/f. We will discuss the physical parameters that affect algorithm accuracy and performance.

Speaker: Ms Yangfan Jiang (Loughborough University)

PSD12poster-Yangfan Jiang.pdf

75 Evaluation of Tomographic Image Reconstruction Techniques for Accurate Spent Fuel Assembly Verification

To realize the non-proliferation and security of nuclear material, the international atomic energy agency (IAEA) considers a tomographic image acquisition technique of spent fuel assemblies as a promising technique to accurately verify rod-by-rod spent fuel conditions stored in a water pool. Our previous research developed and experimentally validated a highly sensitive single-photon emission tomographic (SPECT) system to quickly evaluate the radioactivity distribution of test fuel rods in the Korea Institute of Nuclear Nonproliferation and Control (KINAC). In order to quickly verify the fuel assembly, it is important to develop the high-quality image reconstruction algorithm that enables image acquisition within a short time. The purpose of this study is to evaluate advanced tomographic image reconstruction techniques to accurately identify patterns of missing fuel rods.
Rotational projection image data sets were obtained for 16 patterns of test fuel rods for a total of 900 seconds using the SPECT system installed at KINAC. The projection images were acquired every 5 degrees while four 64-channel detectors rotated 90 degrees. The acquired images were reconstructed in the following methods: filtered back-projection (FBP), simultaneous iterative reconstruction technique (SIRT), order-subset simultaneous algebraic reconstruction technique (OS-SART), and maximum likelihood expectation maximization (MLEM). As a result of quantitative evaluation, the image quality of the MLEM showed the best performance. This algorithm preserved the image intensity and edge, and global homogeneity was significantly better with the reduced generative noise than that of other algorithms. Therefore, to accurately verify the patterns of fuel rods, we improved the signal-to-noise ratio of the tomographic image with the advanced image reconstruction technique. We expect that even for the low-quality measured data with the short-time scan of the SPECT system, this advanced technique will show better discriminability of the patterns of fuel rods in the assembly.

Speaker: Hyemi Kim

76 Characterisation of the spectroscopic properties of p-type Si sensors for X-ray spectroscopy

To meet the requirements of next-generation light sources, STFC has begun work on a new generation of detector technology, capable of operating at MHz frame rates. Although readout electronics are key components of these systems, the choice of sensor material is critical, with high-density semiconductors such as CdZnTe (CZT) required for higher-energy operation. Whilst high-Z materials are commonly used to measure radiation >20keV, the lower electron-hole-pair-generation energy of Si (3.62eV cf. 4.67eV for CZT) offers the potential of improved spectral resolution at lower energies. However, unlike most Si sensors, these compound semiconductors are predominately electron-readout materials. The advantage of p-type-Si sensors is that they are electron readout, meaning a single electron-sensitive readout chip may be used in the measurement of both low- and high-energy X-rays; previously, detector groups were required to design separate versions of an application-specific integrated circuit (ASIC) or operate at sub-optimal performance. Crucially, this will enable a single ASIC technology to have applications across multiple instruments at these light sources.

In this paper, results relating to the characterisation of p-type-Si sensors, each pixelated on a 76$\times$80 array of 300- or 500μm-thick material, and bonded to the STFC HEXITEC ASIC (Veale et al. 2018), are presented. Current-voltage measurements show low <165 pA mm$^{-2}$ leakage currents up to an applied bias of -120V for 500μm-thick devices, and alongside excellent charge-transport properties this results in high-resolution spectroscopic performance. Results demonstrate highly-uniform room-temperature spectroscopic resolution can be obtained across the investigated energy range with average FWHM of <0.8keV measured at 13.81keV. Results are presented alongside studies into the temporal and temperature-based stability of such devices, and the effect of applied bias on energy resolution and charge sharing.

The results presented are highly promising and suggest p-type Si may be used alongside high-Z sensors for X-ray Imaging at future light sources.

Speaker: Ben Cline (Science and Technology Facilities Council)

Ben_Cline_PSD12_poster.pdf

77 An experimental study on frequency-dependent noise-resolution trade-off of an indirect x-ray detector

Noise and spatial resolution are two key intrinsic characteristics to describe the performance of an x-ray detector and quantified by the imaging performance metrics of noise power spectrum, modulation transfer function, and detective quantum efficiency (DQE). To improve two characteristics of an x-ray detector, image processing algorithms are widely used. However, there exists a trade-off between noise and spatial resolution due to the presence of noise-resolution uncertainty in imaging system. In this work, we investigated the influence of image processing on the frequency-dependent noise-resolution trade-off, which is defined as DQE multiplied by the ratio of a pixel size to spatial resolution, with different x-ray doses. We conducted an experiment using a tabletop setup and some linear image processing algorithms such as smoothing and sharpening filters. Measurements were made on a flat-panel detector, DR tech EVS 4343 at 70kVp. Experimental results showed that the frequency-dependent noise-resolution trade-off is hardly influenced by image processing and do not exceed the upper limit at a fixed incident x-ray dose.

Speaker: Mr Hunwoo Lee (Yonsei University)

78 A Monte Carlo study for system development in low dose Molecular Breast Imaging (MBI)

Molecular Breast Imaging (MBI) is a diagnostic technique which uses the radioisotope Technetium-99m to identify lesions within the breast. Cadmium Zinc Telluride (CZT) is a desirable detector material for use in MBI primarily due to its good position resolution. This property makes the detector highly sensitive to 141 keV gamma rays and therefore allows for an isotope of lower activity to be administered to patients without compromising the image quality. The DMatrix Nuclear Imager is a pixelated CZT detector which has been developed by Kromek for applications including Medical Imaging. The detector has previously been characterised at the University of Liverpool for high activity application in Molecular Therapy. We are currently investigating the application of the system towards low activity measurements in MBI.

One of the primary aims of MBI is to optimise a detector system that minimises the dose delivered to the patient. The system consists of both a CZT detector and an imaging collimator, whose properties both contribute to the overall system performance. The collimator is required in order to reconstruct the path of the detected gamma-rays. It is desired that the collimator is optimised such that it complements the sub mm3 resolution achieved (through PSA) within the CZT. The desired imaging properties of good position resolution and high sensitivity are conflicting requirements in terms of collimator design and hence the collimator must be designed such that this trade-off is surmounted.

A Geant4 simulation has been developed to model Kromek’s DMatrix system and explore its response to irradiation of 141 keV gamma rays. The simulation has also been used to model and compare the imaging performance of various collimator designs. The Monte-Carlo study is complemented by a suite of ongoing experimental work. In this talk, the results of the Monte-Carlo study will be presented.

Speaker: Hannah Brown (University of Liverpool)

PSD_2021-HB.pdf

79 Organic Electronic-based Neutron Detectors

We report on the potential use of organic electronic devices applied to radiation detection applications. In recent decades organic electronics has entered the mainstream of consumer electronics. Driven by innovations in scalability and low power applications, and low-cost fabrication methods. The potential for using organic semiconductor electronic devices as radiation detectors, and in particular for neutron detection is reported. We report results of laboratory tests using α, β, and γ sources, and results on response to neutrons using the National Physical Laboratory Van de Graff generator. GEANT4 simulations are being used to provide a detailed understanding of the performance and potential of this emerging technology for radiation detection. Some preliminary results of those simulations are also reported.
Copyright 2021 UK Ministry of Defence © Crown Owned Copyright 2021/AWE

Speaker: Adrian Bevan (Queen Mary University of London (GB))

PSD12_Poster_Bevan.pdf

80 Generation and validation of a theoretical signal database for the Segmented Inverted-coaxial Germanium (SIGMA) Detector

The prototype SIGMA detector is the first p-type segmented inverted-coaxial germanium detector to be manufactured for γ-ray tracking and imaging purposes [1,2]. The γ-ray tracking and imaging capability of SIGMA requires a high precision of measuring the interaction positions of γ-ray radiation with the detector which is strongly dependent upon the achieved position resolution. The γ-ray interaction position is determined by extracting the charge pulses from both a small p-type point contact on the rare face of the detector and the outer n-type electrode which is electrically segmented into 18 segments. In order to determine the position resolution of SIGMA, pulse shape analysis (PSA) methods using chi-squared minimisation technique will be applied which require a signal database of all possible positions of γ-ray interactions with the detector volume. For this reason, the detector response has been simulated using Agata Detector Library (ADL) [3] to generate theoretical pulse shapes for the SIGMA detector. The simulated signals were validated against their equivalent experimental signals at known positions in order to build such signal database which is currently being developed.

Speaker: AHMED ALHARBI (University of Liverpool (Nuclear Group))

Applications in Particle Physics 2

Conveners: Jon Lapington (University of Leicester), Nigel Watson (University of Birmingham (GB))

81 Applications in Particle Physics

Speaker: Petra Riedler (CERN)

PSD2021_priedler.pdf

82 Status and plans for the CMS High Granularity Calorimeter upgrade project

The CMS Collaboration is preparing to build replacement endcap calorimeters for the HL-LHC era. The new high-granularity calorimeter (HGCAL) is, as the name implies, a highly-granular sampling calorimeter with approximately six million silicon sensor channels (~1.1cm^2 or 0.5cm^2 cells) and about four hundred thousand channels of scintillator tiles readout with on-tile silicon photomultipliers. The calorimeter is designed to operate in the harsh radiation environment at the HL-LHC, where the average number of interactions per bunch crossing is expected to exceed 140. Besides measuring energy and position of the energy deposits the electronics is also designed to measure the time of their arrival with a precision on the order of 50 ps. In this talk, the reasoning and ideas behind the HGCAL, the current status of the project, the many lessons learnt so far, and the challenges ahead will be presented.

Speaker: Eva Sicking (CERN)

EvaSicking_HGCAL_Status_Plans_PSD21.pdf

83 Development of CMOS Pixel Sensor prototypes for the high-rate CEPC vertex detector

The proposed Circular Electron Positron Collider (CEPC) imposes new challenges for the vertex detector in terms of material budget, spatial resolution, readout speed, and power consumption. CMOS Pixel Sensor (CPS), as one of the promising candidate technologies, has been studied within the CEPC vertex detector R&D activities since 2015. According to the latest collider design and study on the beam-induced background, the highest hit rate for the vertex detector is expected to be ~107/cm2/s. The TaichuPix chip is a CMOS Pixel Sensor being developed to meet the highest hit rate requirement of CEPC vertex detector. Two small scale prototypes capable of achieving a hit rate up to 36 MHz/cm2, were developed in a 180 nm CMOS process. This talk presents the dedicated improvements on the design of in-pixel readout to achieve a pixel pitch of 25 μm and a fast readout capability of 40 MHz. Two new fast in-pixel digital readout designs, benefiting from the FE-I3 and ALPIDE approaches, have been implemented. The readout of the pixel array is based on a new proposed “column-drain” architecture. Pixels are arranged in double columns, with priority encoder within column and timestamp recorded at the end of double column (EOC). All the double columns are read out in parallel, in order to minimize the dead time. When a hit is detected in one of the pixels, the end of column circuitry stores the current time stamp with a resolution of 25 ns. The data whose timestamp matches with the trigger (with a time window of 175 ns) are buffered for output in case of trigger mode. The two TaichuPix prototypes were characterized with electrical and radioactive sources in laboratory. The test results on the chip functionality and the noise and threshold performance before and after ionizing radiation are reported.

Speaker: Ying Zhang (IHEP, Chinese Academy of Sciences (CN))

PSD_20210915_ZhangYing.pdf

84 New beam position detectors for NA61/SHINE experiment

NA61/SHINE is a multi-purpose fixed-target experiment located at the Super Proton Synchrotron at CERN. The main goals of the experiment include studies for physics of strong interactions, neutrino physics, and cosmic-rays physics. After the upgrade of the detector system, scheduled to be completed this year, the experiment will collect data up to 1 kHz event rate (factor 10 increase). The development of new beam position detectors, used to measure the positions of incoming beam particles in the transverse plane, is a crucial part of the upgrade. The previous set of beam position detectors was based on the proportional gas chambers.

Instead, two new kinds of beam position detectors are prepared and tested. One of them is the scintillating fibre detector with a multi-anode photomultiplier readout. It is built of two perpendicularly arranged ribbons, each consisting of two shifted layers of green-emitting scintillating fibres with a diameter of 250 µm. The second type of detector is based on the single-sided silicon strip detector (Hamamatsu S13804).

The talk will give an overview of both detectors' concepts and will present the results of tests and commissioning experiments.

Speaker: Yuliia Balkova (University of Silesia (PL))

BPD_SHINE_PSD12.pdf

85 Towards MightyPix, an HV-MAPS for the LHCb Mighty Tracker Upgrade

The Mighty Tracker is a proposed upgrade to the downstream tracking system of LHCb for operations at high luminosities starting with the LHC Run 5 data taking period. It foresees the replacement of the most central area of the scintillating fibre tracker with HV-CMOS pixel sensors. Due to the increased luminosity of the LHC, occupancy would be too high for track reconstruction in the fibre tracker and the fibres could no longer withstand the radiation damage. HV-CMOS sensors have demonstrated a significant radiation tolerance and good performance making them an ideal choice of technology for the LHCb experiment.
Monolithic active pixel sensors (MAPS) fabricated in HV-CMOS processes provide fast charge collection via drift and allow the implementation of the readout on the same die as the sensitive volume. Due the use of commercial processes, these sensors can be fabricated at low cost as no hybridisation with bump bonds is required. Since they are not fully depleted, the inactive volume can be thinned away.
A dedicated sensor called the MightyPix is developed for this programme. It is based on the successful HV-MAPS families MuPix and ATLASpix and tailored to the requirements of LHCb. To demonstrate the feasibility of this technology for the LHCb environment, prototypes have been irradiated. These sensors are investigated in terms of efficiency, time resolution and power dissipation in temperature controlled environments. Results of measurements are presented.

Speaker: Jan Patrick Hammerich (University of Liverpool (GB))

PSD2021_MightyPix.pdf

15:50 Coffee/Tea

Poster Session 3 (Applications in Particle Physics)

Applications in Particle Physics

Conveners: Paul Sellin (University of Surrey), Ioannis Kopsalis (University of Birmingham (GB))

86 Construction and Operation of the CMS Phase-1 Silicon Pixel Detector at the LHC

The CMS Phase-1 Pixel Detector was designed to cope with an instantaneous luminosity 2 x 10^34 cm-2 s-1 and 25 ns bunch spacing with very small efficiency loss. The upgraded detector has 124M channels that features a 4-hit coverage in the tracking volume. DC-DC converters were used to deliver more power to the detector without the need of replacing the cable plant. CO2 based cooling was implemented and carbon based structures were used to reduce material in the tracking volume. The data acquisition system was upgraded to accept higher event rates and a digital data format from the detector front-ends. The detector was installed in early 2017 and has been successfully operated since then. In this presentation, the construction and assembly, operational experience and the performance of the pixel detector at the LHC will be discussed.

Speaker: Somnath Choudhury (Indian Institute of Science (IN))

CMS-Pixel-Detector.pdf

87 The upgrade and performance of the LHCb RICH detector system

The LHCb experiment at CERN studies b- and c-hadron decays in the forward region. Physics analyses in LHCb rely on the Ring Imaging Cherenkov (RICH) detector system for the charged hadrons identification in a wide momentum range. The RICH system has provided particle identification with excellent performance during Runs 1 and 2 of LHC and it's currently undergoing a substantial upgrade to deal with the expected five-fold increase of luminosity in Run 3. The upstream RICH optics and mechanics will be improved and the photodetectors will be upgraded by installing multi-anode photomultiplier tubes. In addition, the new readout electronics will allow a 40 MHz continuous data taking. An overview of the RICH expected performance and a summary of the upgrade activities will be presented.

Speaker: Edoardo Franzoso (Universita e INFN, Ferrara (IT))

The_upgrade_and_performance_of_the_LHCb_RICH_detector_system.pdf

88 Background in the CMS Drift Tubes: measurements with LHC collision data and implications for detector longevity at HL-LH

In the barrel region of the CMS muon spectrometer Drift Tubes (DT) are installed. They are used for offline tracking of muons and also provide standalone trigger capabilities. Though an upgrade of the DT system electronics is foreseen for High-Luminosity LHC (HL-LHC), the present DT chambers won’t be replaced, hence they will be called to operate enduring integrated doses far beyond what they were initially designed for. Together with accelerated ageing studies, accurate measurements of the background-induced hit rates and currents observed over Run-2 are critical to assess the longevity of the DT chambers and to make projections of the expected performance of the system throughout HL-LHC. This report presents the state of the art of the studies about the background affecting the DT system, and links them to results from longevity studies performed exploiting the CERN high-intensity gamma irradiation facility (GIF++). Moreover it describes all measures that have been put in place, by the end of Run-2 and over LS2, to mitigate ageing and, where possible, reduce background level, with the aim of maximising the performance of the DT detector throughout HL-LHC.

Speaker: Lisa Borgonovi (Universita e INFN, Bologna (IT))

posterPSD12_LBorgonovi_v3.pdf

89 Application of material budget imaging for the design of the ATLAS ITk strip detector

The technique of material budget imaging (MBI) allows to experimentally assess the material budget $\epsilon=x/X_0$ of a material with thickness $x$ and its radiation length $X_0$. Here, multi-GeV electrons from a test beam facility such as the DESY-II test beam are used. This novel technique exploits the fact that the beam particles are deflected by multiple Coulomb scattering following a distribution of the deflection angle with a center at zero and a width depending on the traversed material. By reconstructing the individual kink angles from the measured particle trajectories in a high resolution beam telescope, the material budget can be extracted by applying appropriate models of multiple scattering theory, such as the Highland formula.
On the one hand, various materials with known material budgets were measured to calibrate the MBI technique and study also different systematic effects such as the beam telescope's acceptance and the variation of the beam energy. On the other hand, a number of material samples planned in the design of the local support structures of the new ATLAS Inner Tracker (ITk) strip detector were investigated to extract the according radiation length values not known beforehand. Here, also the possibility of two-dimensional imaging of complex structures was successfully demonstrated for carbon-fiber based sandwich structure (the "petal core") allowing an even deeper analysis of the detector design.
Overall, the potential of the MBI technique covers a wide range of applications: from the design of high-energy particle detectors over industrial investigations of high-Z materials up to applications in medical imaging ("electron CT").

Speaker: Jan-Hendrik Arling (Deutsches Elektronen-Synchrotron (DE))

PSD12_Poster178_Arling.pdf

90 Results from ATLAS-ITk Strip Sensors Quality Assurance Testchip

The pre-production of the strip sensors for the Inner Tracker (ITk) of the ATLAS Upgrade detector at CERN has finished, comprising about 5% of the total number of sensors to be fabricated during the 4-year production period (approximately 22000). All sensors are tested by the collaboration according to the Quality Control procedures. For Quality Assurance, a number of test structures, designed by the collaboration and put together in a full testchip, are produced in every wafer together with the main sensors and the other QA test structures like mini sensors and large diodes by the foundry (HPK). Samples of these testchips are tested for every batch of sensors. One testchip is tested before irradiation for every batch fabricated in order to monitor the stability of the key technological and device parameters. Also for every batch, one test chip is irradiated either with gammas or protons in order to account for ionization damage. Additionally, one mini per batch is irradiated either with neutrons or protons to account for displacement damage effects. All this effort is carried out by 7 irradiation and test sites.

The results from about 100 testchips tested during the pre-production period will be shown and analyzed. The results of the pre-production batches show that all parameters remain under specifications before irradiation. After irradiation, all parameters remain under specifications except for some structures damaged by handling, for which replacement chips have been irradiated. Some of the newly designed structures show testing limitations for a few of the parameters.

These results help to accumulate enough statistics in order to establish what we call “soft” thresholds for those parameters that are not directly related to specifications. These soft thresholds will be used as Upper and Lower Control Limits (UCL and LCL) in the production control of the technological parameters for QA.

91 Interferometric techniques with high resolution emulsion detectors

I will present an interferometric technique suitable for the measurement of particle masses. The goal of this study is to attain the capability of measuring particle-antiparticle mass ratio in a way that is independent of particle electric charges, a technique that is gaining interest in view of recent developments of experiments looking for CPT violations and antimatter gravitational fall.
In order to obtain an accurate estimate of the mass ratio, the proposed method relies on the possibility to have a very high-resolution detector which can reliably respond to low energy particles and antiparticles.
Nuclear emulsions are position sensitive detectors that feature these fundamental characteristics. Recently, super-fine-grained nuclear emulsions have been developed using a new method, which leads to a resolution up to 50 nanometers (A. Alexandrov et al; Sci. Rep. 2020, 10, 18773).
Furthermore, nuclear emulsions have already been successfully tested with antimatter: the capability to reconstruct antiproton annihilations with micrometric resolution has been demonstrated by the AEGIS collaboration; the high detecting efficiency for low energy antiparticles has been proved by the QUPLAS collaboration with the demonstration of positron interferometry (S. Sala et al; Sci. Adv. 2019, 5, eaav7610).
Therefore, thanks to the improved resolution of the nuclear emulsions and their tested response to low energy particles, the emulsion-based detector represents an ideal device for this quantum interferometry study, where micrometric fringes of the periodic spatial distribution generated by the interferometer have to be measured.

Speaker: Eleonora Pasino (Università degli Studi e INFN Milano (IT))

poster-Eleonora-Pasino.pdf

92 High-performance HV-CMOS sensors for future particle physics experiments - An overview

Traditional hybrid silicon sensors are the most common tracking sensor technology in current particle physics experiments with high rates. However the limitations imposed by their composite structure make them unsuitable for many future experiments that require low material budget and high spatial resolution. High Voltage-CMOS (HV-CMOS) sensors, due to their significant advantages, are emerging as a prime candidate for future tracking applications that have extreme requirements on the material budget, granularity, time resolution and radiation tolerance.

HV-CMOS sensors integrate both the silicon sensor and readout ASIC into the same silicon substrate, thus eliminating the need for complex and laborious bump-bonding. The high voltage, at which the substrate is biased, creates a wide depletion region for fast charge collection by drift and high radiation tolerance. The feasibility of integrating analog and digital readout electronics on the same chip allows the production of fully monolithic HV-CMOS sensors. Therefore, HV-CMOS sensors have become a promising solution for future particle physics experiments, such as the Mu3e experiment, future upgrades of the Large Hadron Collider (LHC) and the Circular Electron Positron Collider (CEPC).

Despite the major improvements already demonstrated by HV-CMOS sensors, the enormous challenges set by future experiments demand substantial research to achieve further enhancements. The main goal of our R&D programme at Liverpool is to push the boundaries of HV-CMOS sensors to achieve a step-change improvement in their performance, especially in terms of single point resolution, fast-timing capability and radiation tolerance. This talk will give an overview of the latest developments in HV-CMOS sensors done by our group and present the design and measured results of a new HV-CMOS prototype chip. This chip is designed to further improve the radiation tolerance and time resolution of HV-CMOS sensors.

Speaker: Chenfan Zhang (University of Liverpool (GB))

PSD12_poster_Chenfan_V2.1.pdf

93 Precision Antihydrogen Annihilation Reconstructions using the ALPHA-g Apparatus

The ALPHA (Antihydrogen Laser PHysics Apparatus) experiment aims to provide a possible solution to the baryonic asymmetry problem by testing CPT (charge conjugation, parity reversal, time reversal) theory and observing whether antimatter follows Einstein's Weak Equivalence Principle (WEP), where the acceleration due to gravity that a body experiences is independent of its structure or composition. A measurement of this nature has never been done before, as previous experiments used charged particles which meant the experiments were dominated by electromagnetic forces. The ALPHA-g apparatus will use electrically neutral antihydrogen produced in a vertical Penning-Malmberg trap and hold the antihydrogen in a magnetic well. Once the antihydrogen is released, the position of the resulting annihilation can be reconstructed with a radial TPC (time projection chamber) surrounding the trapping volume [1].

Position information can be determined by the signal generated by the products of the annihilations as they travel through the TPC. Tracing these products accurately to their point of origin is imperative to understanding the direction of antihydrogen. I will focus on how these calculations are done through simulations, and how the process will compare to real data. This data will be used to measure the gravitational mass of antihydrogen, making this a crucial step in testing the fundamental symmetry of matter and antimatter. The ALPHA-g apparatus is currently being commissioned at CERN, and the first gravitational measurements of antihydrogen are expected to begin in October 2021.

[1] Capra, A., et al. “Design of a Radial TPC for Antihydrogen Gravity Measurement with ALPHA-g.” Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016).

Speaker: Ms Pooja Woosaree (University of Calgary)

PSD2021_Poster_PoojaWoosaree_final.pdf

94 Serial powering and signal integrity characterisation for the TEPX detector for the Phase-2 CMS Inner Tracker

The entire CMS silicon pixel detector will be replaced for operation at the High Luminosity LHC. The novel scheme of serial powering will be deployed to power the pixel modules and new technologies will be used for a high bandwidth readout system. In this contribution the new TEPX detector will be presented, with particular focus on a novel concept to provide both power and data connectivity to the modules through a disk shaped PCB. As TEPX also features the longest serial powering chains in the CMS Inner Tracker, an emphasis on serial powering results will be shown, together with signal integrity and data transmission performance.

Speaker: Kyle James Read Cormier (Universitaet Zuerich (CH))

PSD12_Poster_CMS_TEPX_testing_09.2021.pdf

95 CMS Phase-1 Pixel detector refurbishment during LS2 and readiness towards the LHC Run-3

The CMS Phase-1 pixel detector was extracted from the underground cavern after the end of the LHC Run-2 in 2019 and has been kept cold to protect the silicone sensors during the long shutdown period (LS2) in 2019-2021. The LHC is now preparing for the next installment of the data taking beginning 2022. The Phase-1 pixel detector is scheduled to be installed this year and is going through a series of refurbishment and repairs to improve the quality of the collected data and enhance the operational experience. The innermost barrel layer has been replaced with new modules and features improved readout chips (PROC600v4), front-end ASICs (TBM10d), and circuit boards to rectify the issues discovered during the previous data taking. The forward pixel detector has been equipped with new cooling inlets for safe handling and features a revised high-voltage power distribution scheme to better match the low-voltage granularity. All the DC-DC converters have been replaced with a new production, consisting of an improved ASIC (FEAST2.3) to prevent them from breaking during operation. Overall, this talk will summarize the refurbishment work of the pixel detector during LS2, and highlight the readiness towards the LHC Run-3 after installation and commissioning.

Speaker: Mr Lars Noehte

Lars Noehte.pdf

96 2S-module prototyping and qualification for the CMS Outer Tracker upgrade at the HL-LHC

In preparation for the High Luminosity LHC, the whole tracker detector of the CMS experiment will be exchanged within the Phase-2 Upgrade until 2027. The new outer tracker will be made of approximately 13000 silicon sensor modules called 2S modules (consisting of two parallel mounted silicon strip sensors) and PS modules (one pixel and a strip sensor combined in a module). These modules provide tracking information to the Level 1 trigger by correlating the hit information of both sensor layers and, thus, allowing to discriminate particle tracks by their transverse momentum. To guarantee successful operation during data-taking, the production of the outer tracker modules has to fulfill strict requirements. This talk will present practical procedures about assembly, electrical, thermal and vibration tests performed at CERN for supporting the 2S module development and qualification.

Speaker: Fengwangdong Zhang (University of California Davis (US))

psd12.pdf

97 Tracker alignment of the CMS detector

The positions of the nearly twenty-thousand silicon sensors of the CMS central tracking system must be determined with a precision better than their intrinsic resolution in order to provide an optimal reconstruction of charged particle trajectories. The procedure, referred to as alignment, includes also the adjustment of the orientations and the determination of the deviation from flatness of the sensor surfaces.

Data-driven methods used to carefully align the detector and validate the alignment will be presented with CMS Run-2 data, collected from 2016 to 2018. Systematic distortions such as weak modes are discussed, as well as the impact of the variation of the conditions during data taking over time, in particular effects related to the radiation damage.

Finally, we illustrate the impact on physics of the recent developments included in the legacy reprocessing, which was performed with the aim to greatly improve the physics potential for precision measurements, such as the reconstruction of the invariant mass spectrum of the dilepton systems.

Speaker: Nazar Bartosik (Universita e INFN Torino (IT))

poster_bartosik_v0.pdf

98 Development of position-sensitive silicon detector for ILC calorimeters

Position-sensitive silicon detector (PSD) is a silicon pad sensor with resistive surface connecting to electrodes on corners of the cell. PSDs are widely used in laser optics, and also used as detectors for heavy ions, while the application to particle physics has been limited to smaller signal due to smaller energy deposit, which degrades position resolutions. We are investigating PSD for MIPs with thick silicon sensors (650 um) to be used as sensors at innermost layers of highly-granular calorimeters to improve pointing resolution of incident particles. Basic measurements of the prototype sensors with lasers and radioisotopes will be presented. Application to ILC calorimeters, and further possibility to include an avalanche layer to improve the position resolution will also be discussed.

Speaker: Taikan Suehara (Kyushu University (JP))

psd12-poster-214-suehara.pdf

99 Cylindrical GEM Inner Tracker for the BESIII experiment

A ten years extension of the data taking of the BESIII esperiment, recently approved, motivated an upgrade program both for the leptonic collider BEPCII (Beijing Electron Positron Collider II), that host the experiment, and for some of the subdetectors, that compose the spectrometer.
This presentation will focus on the upgrade foreseen for the inner tracker. The present multilayer drift chamber is suffering of ageing and the standing proposal is to replace it with a detector based on Cylindrical GEM (Gas Electron Multiplier) technology. This Inner Tracker is composed of three layers of cylindrical triple-GEMs. The CGEM-IT will not only restore the design efficiency, but also improve the secondary vertex reconstruction and the radiation tolerance. The custom developed mechanic and electronic design will guarantee excellent performance in the wide range of incident angles in a 1 Tesla magnetic field.
The front-end electronics is composed by 64 channels ASIC featuring a fully digital output that allow to be operated in trigger-less mode and can provide analog charge and time measurements. All these components, together with optimized gas mixture, gain value settings and reconstruction algorithms, will allow to reach a position resolution to the level of ∼130 µm in the transverse plane and better than 350 µm along the beam direction. In this presentation, the general status of the project will be presented, with a particular focus on the recent preliminary results from the cosmic data taking and the future plans.

Speaker: Sara Morgante (INFN Fe - IHEP)

Poster PSD12_BESIII_correct.pdf

100 A 4.5GHz to 5.6GHz PLL in 55 nm CMOS for High-Energy Physics Experiments

Low jitter and radiation tolerant Phase-Lock-Loop (PLL) has been prevailingly researched and used in high-energy physics experiments. This paper presents the design and test results of a radiation tolerant, 4.5GHz to 5.6GHz PLL ASIC fabricated in 55 nm CMOS technology. The PLL ASIC consists of a phase frequency detector (PFD) circuit, a charge pump (CP) circuit, a low pass filter circuit (LPF), a LC voltage controlled oscillator circuit (LCVCO) with capacitor array, a feedback divider circuit and SPI module. In order to obtain low DC leakage current (about 500 pA) and reduce dynamic mismatch, the CP uses two unity-gain feedback operational amplifiers to keep the charge pump output common mode voltage constant. To obtain a wide range of frequency, the LCVCO can change the oscillation frequency by adjusting the capacitance value of the novel capacitor array. The tuning capacitor array consists of MOM capacitor units with three binary controlled NMOS switches and two big resistors. Besides, the LCVCO can improve the Q factor degradation due to the source/ drain leakage current from the binary controlled NMOS transistor.
The whole ASIC features a size of 1200 μm x 900 μm. The PLL covers a wide-frequency range from 4.5GHz to 5.6GHz, consuming a total power of 25 mW from the post layout simulation. At 5.12 GHz, the phase noise is -115 dBc/Hz @ 1MHz offset. The chip has been taped out and the tests are planned to be conducted in this May. The ASIC die will be glued and bonded to a high- frequency print circuit board (PCB) to which the DC supply voltage, SPI control signal and reference clock input can be applied. The electrical test and total ionizing dose (TID) test will be performed. The test results will be reported in the meeting.

Speakers: Cong Zhao (Central China Normal University), Di Guo (Central China Normal University)

PSD12-Zhao-PLL ASIC Poster.pdf

101 A congestion awareness and Fault-tolerance Readout Network ASIC for High-Density Electrode Array Targeting Neutrinoless Double-Beta Decay Search in TPC

Among the current and planned experiments of neutrinoless double-beta decay (0νββ), the high-pressure gaseous TPC stands out for its excellent energy resolution, low radioactive background and good scalability. Moreover, high position resolution can be maintained with an appropriate charge readout scheme for TPC to further suppress the background through ionization imaging. A low noise sensor, Topmetal-S, is being developed which, even without gas gain, the energy resolution requirement could be met. To realize a ton-scale TPC, approximately 100,000 Topmetal-S need to be laid on a meter-sized plane with a pitch of 5~10mm. The one of greatest challenges is reliable high-density sensor readout. A readout network ASIC is implemented and will be integrated into Topmetal-S as a router. A sensor network is built by establishing local connection among nearby sensors to ensure the tightness and radioactive purity of the high-pressure TPC. As a node of the network, each sensor not only generates and transmits its own data, but also forwards data from nearby sensors, and data is finally transferred to the edge of the network and received by a computer.
The test results of the first porotype of readout network ASIC show that the risk of data loss increased in the nearby sensors of the fault sensors. In addition, if the sensor in the same line is hit four or more times, it will cause data loss. Therefore, this paper proposed a distributed, self-organizing, fault-tolerance, and congestion awareness readout network ASIC and a distributed, adaptive and fault-tolerance-XY routing algorithm. The simulation shows that the throughput of the readout network reaches 8252.16 Mbit/s and the latency of the network is less than 120 us. Then the design has been verified and tested on the FPGA. The ASIC is implementing on a 130 nm CMOS process now and submitted it in May 2021.

Speaker: bihui you (Central China Normal University)

readout network PSD12.pdf

102 A radiation tolerant 16 Gbps 1:16 Deserializer for High-Energy Physics Experiments

Deserializer with high speed and radiation tolerant features is used as key component of data transmission system in high-energy physics experiments. It is mainly used in the downlink transmission to realize serial-to-parallel conversion of data. This paper presents the design and test results of a 16 Gbps 1:16 deserializer chip fabricated in 55 nm CMOS technology. The chip adopts a tree-type tap structure, consisting of an input equalizer stage, four levels of half-rate 1:2, 2:4, 4:8, 8:16 Demultiplexer (DEMUX) modules, corresponding frequency dividers. The input equalizer stage is used to compensate for the high frequency loss caused by the transmission line on PCB and the bonding wire. The first 1:2 DEMUX receives the 16Gbps CML signals from the equalizer stage, performs the first 1:2 transform, then transmits to the following levels. The final 8:16 DEMUX outputs 16 parallel data with 1 Gbps. The frequency divider divides the externally input 8GHz clock to provide a half-rate clock for each stage of DEMUX. In order to improve the bandwidth of the high-speed 1:2 DEMUX and high-frequency divider, and save voltage margin, their latches adopt a CML structure without tail current source. We designed duty cycle correction circuit and clock alignment circuit to recover duty cycle and align clock edges in clock path.
The whole chip consumes 305 mW when working at 16 Gbps. The dimension of the designed deserializer chip is 2mmX3mm, including 58 PADs. The post-layout simulation results demonstrate that the whole chip work functionally at the target speed and 16 wide-open eyes are verified at the all output channels. The total jitter (TJ) of each output channel (1 Gbps/ch) is 28.2ps averagely. This chip has been taped out and the tests are planned to be conducted in this March. The test results will be reported in the meeting.

Speakers: Qiangjun Chen (Central China Normal University), Di Guo (Central China Normal University)

Deserializer_Poster.pdf

103 DAQ Control Signal Codec for Time of Flight AFP Detector

The particle physics experiments produce the data in the order of tens GB per hour. Due to the limited resources for data storage and offline processing this amount has to be reduced with respect to the events strongly related to the ongoing experiment. Data acquisition (DAQ) system is the key component dedicated to data collecting and storing at different stages of the particle detector system. The Codec takes the commands from the Digital Trigger Module (DTM) in Time-of-Flight (ToF) detector chain at ATLAS Forward Proton (AFP) project. These commands are then encoded and prepared for the fast serial transfer via the 265 m long coaxial cable located between the CERN LHC accelerator and the rack room where the DAQ is placed. As the LHC operating frequency (bunch clock) is 40 MHz the transfer rate of the 5-bit data frames is set to 400 MHz. The received signal at the end of the coax is distorted mainly due to the parasitic capacitance and limited output power of the cable buffer of the transmitter. Therefore, the receiver implements the circuitry for the restoring of the input signal. Then the decoder processes the received data frame and prepares the signals for control of the DAQ. The system as a whole will be thoroughly tested in DESY and CERN and consequently installed at LHC.

Speaker: Jan Zich (University of West Bohemia (CZ))

DAQ Control Signal Codec for Time of Flight AFP Detector.pdf

X-ray and Gamma Ray Detectors 2

Conveners: Paul Sellin (University of Surrey), David Smith (Brunel University London)

104 X-ray and Gamma Ray Detectors (in-person)

Speaker: Helen Boston

PSD 2021 HCB .pdf

PSD 2021 HCB .pptx

105 Improving Position Resolution in Pixelated CZT Detectors through Collimated Gamma-Ray Scanning for use in Molecular Breast Imaging Applications

Current breast cancer screening techniques suffer from reduced diagnostic performance for patients with mammographically dense breasts. An alternative screening method that overcomes this is Molecular Breast Imaging (MBI), which uses the 140.5 keV gamma-emitting tracer technetium-99m in conjunction with a gamma-camera to image breast tissue.

A gamma-camera is being developed for this application that makes use of a room-temperature pixelated CZT detector in conjunction with a collimator mask. The detecting crystal was taken from a Kromek D-Matrix gamma-ray imager and is 22 x 22 x 5 mm, with a planar cathode and 11 x 11 pixelated anode. This a provided an intrinsic position resolution of 2 x 2 x 5 mm. Pulse Shape Analysis (PSA) techniques can be applied to the signals to improve the position resolution further. The D-Matrix unit provided only timing and energy information via ASIC coupling, so a readout system was designed and constructed that enabled the digitisation and analysis of the raw signals.

Characterisation of the crystal’s signal response was performed using high-precision collimated gamma-ray scanning. A cobalt-57 source and a tungsten collimator were used to produce a tightly collimated beam of 122.1 keV gamma rays, analogous to those from technetium-99m, to map the signal response as a function of interaction position. A database of signals from constrained positions was thus formed and used to characterise the charge collection and transient signal response of the crystal. Signal-parameterisation based PSA methods were developed using this database and implemented in order to achieve sub-voxel position resolution both laterally and in depth. The developed algorithms are intended for implementation in the digital ASICs of future detecting systems.

Speaker: Ellis Rintoul (The University of Liverpool)

PSD2021_Presentation.pdf

106 Spectroscopic X-ray Imaging at MHz Frame Rates – The HEXITEC$_{MHz}$ ASIC

The HEXITEC$_{MHz}$ ASIC has been developed for the HEXITEC$_{MHz}$ Detector System, to deliver spectroscopic x-ray imaging at frame rates up to 1MHz for future high-flux-rate applications. Optimised for sensing electron signals from detector materials such as CdTe, CZT, GaAs, Ge and p-type silicon detectors, the design has an array of 80x80 pixels on a pitch of 250$\mu$m, with each pixel capable of measuring single x-ray photons up to energies of 200keV, with a resolution of 1keV FWHM.

Further improvements in the spatial and spectroscopic resolution are possible due to the pixel’s ability to simultaneously sense positive signals up to 20keV induced by internal weighting potential effects from electron signals on neighbouring pixels.

A count rate limit of around 10$^{6}$ photons s$^{-1}$ mm$^{-2}$ is achieved by converting the signals from all pixels every 1$\mu$s using 12-bit time-to-digital converters – an improvement of two orders of magnitude over previous HEXITEC ASICs. To save power, each converter is shared between groups of eight pixels.

Each 76.8kbit data frame is Aurora 64b/66b encoded and serialised over 20 lanes of differential CML, all operating in parallel at 4.1Gbps.

In this paper, we present details of the design, and possibly preliminary test results from the ASIC.

Speaker: Lawrence Jones (UKRI STFC)

HEXITEC_MHZ.pdf

107 New developments on FBK position sensitive silicon photomultipliers

Silicon Photomultipliers (SiPMs) are solid-state single photon detectors that show excellent performance in a wide range of applications. In 2015 FBK (Trento, Italy) developed a position sensitive SiPM technology, called “linearly-graded” (LG-SiPM), that showed position reconstruction resolution below 250 µm on an 8x8 mm² device area with only four readout channels and minimal distortions. This technology was proven effective in the readout and discrimination of pixelated LYSO crystals for PET applications (J. Du 2018) and in the 3D reconstruction of alpha particle tracks in an optically readout TPC (A. Gola 2020). Both these applications employed multiplexing techniques to reduce the number of readout channels for a 2x2 SiPM arrays while maintaining the position sensitivity across the surface.
In this work we present the new developments on LG-SiPM. In particular the new SiPMs have a larger active area (10x10 mm²) and they are based on NUV-HD technology, having a peak photon detection efficiency at 420 nm, as opposed to the older technology with peak sensitivity around 550 nm. With these SiPMs we aim to demonstrate the readout channel multiplexing technique applied to larger areas, up to 3x3 elements arrays for a total surface of 30x30 mm².
We also present a one-dimensional position sensitive detector developed for the readout of scintillating fiber mats or for X ray spectroscopy detectors. This sensor is rectangular, with a form factor of 10:1, and it has position sensitivity across the longest dimension. The second dimension is kept small in order to reduce the dark counts and improve the spatial resolution also at low light levels. As in the previous device the 1D version provides high resolution with a low number of readout channels and can be combined into linear arrays with channel multiplexing.

Speaker: Stefano Merzi (FBK)

New developments on FBK position sensitive silicon photomultipliers.pdf

108 A monolithic silicon pixel sensor in SiGe BiCMOS for the FASER high granularity pre-shower detector.

A monolithic silicon pixel detector is being designed in 130nm SiGe BiCMOS process of IHP to realize a pre-shower detector for the FASER experiment at CERN.
The pre-shower is designed to discriminate electromagnetic showers produced by two primary photons with an energy in the range 100 GeV to 1 TeV and with a separation as small as 200 micron. The monolithic ASIC will have hexagonal pixels of 65 micron of side, each capable to measure a charge in the range of 1 fC to 60 fC. To reconstruct the profile of the electromagnetic shower, the sensor must be able to read hundreds of pixels firing at the same time. The detector planes will have a time resolution of approximately 200 ps. The power budget is limited to less than 150 mW/cm2.
The pre-production prototypes, submitted in June 2021, implement two alternative architectures to enable the readout of many pixels with a very large dynamic range.

Speaker: Fulvio Martinelli (EPFL - Ecole Polytechnique Federale Lausanne (CH))

PSD12_Birmingham_FASER.pdf

109 Reception and Conference Dinner at the Birmingham Botanical Gardens

Coaches leaving from the Conference Hotel at 19.00

Thursday, 16 September

Poster Session 4 (Position Sensitive Fast Timing Detectors)

Position Sensitive Fast Timing Detectors

Conveners: Ioannis Kopsalis (University of Birmingham (GB)), Philip Patrick Allport (University of Birmingham (UK))

110 Performance of LGAD sensors for the ATLAS High-Granularity Timing Detector

We report on the layout and performance of Low-Gain Avalanche Detectors (LGAD) produced for the ATLAS High Granularity Timing Detector (HGTD) foreseen for the HL-LHC upgrade of the ATLAS experiment. The HGTD is a multi-layer silicon-based detector with a total active area of 6.4 m2 covering the pseudo-rapidity region between 2.4 and 4.0 with timing sensors with primary resolution of at least 50 ps/hit, and capable of providing 30-50 ps/track time resolution. This represents the first large scale application of the LGAD technology.

Sensors with an active thickness of 50 µm and 35 µm were produced with common masks and different combinations of doping profile of the gain layer. The power dissipation and breakdown voltage are determined from I-V measurement, doping profile of the gain layer and the bulk from C-V data. The dynamic properties of the LGADs were determined by charge collection measurements using laser and charged particles. Samples of the sensors are irradiated with neutrons, protons and gammas to study the radiation-hardness. The dependence of the gain and of the time resolution on bias voltage and fluences and the early results of the LGADs bump-bonded to the ALTIROC1 chip will also be presented.

Speaker: Han CUI (CERN)

PSD12-poster.pdf

111 The coordinate sensitive detector based on the MA-20 multianode PMT with high space and time resolution

The work is dedicated to the discussion of the possibility of creating a position-sensitive detector
with both high coordinate reconstruction and time resolution. The work is presented the simulation
results and the experimentally obtained data for a prototype detector on the basis of
a multianode PMT MA-20 and a linear assembly of scintillating crystal or plastic strips.

The multianode position-sensitive PMT MA-20 has a semitransparent bi-alkaline photocathode
with the size of the sensitive area of $10 \times 200\ mm ^2$, 20 evaporated type bi-alkaline
dynodes of the same length and 20 separate anodes.

An assembly of scintillating strips made of GSO (gadolinium orthosilicate) crystals
with an element size of $3 \times 10 \times 50\ mm^3$, or of BGO (bismuth germanate)
crystals with an element size of $5 \times 15 \times 40\ mm^3$ also, and finally
set of plates made of a plastic scintillator
were used for experimental measurement of a coordinate resolution of the detector
prototype. Coordinate resolution was determined by the position of the center
of gravity of charges from neighboring dynodes.

The use of a multi-anode photomultiplier in combination with the array of crystal or plastic scintillators allows one to get the detector with a high performance in both
spatial and time resolution and also a low level of intrinsic noise in comparison,
for example, with silicon PMT’s. An ideal resolution simulation was performed for
a system consisting of a one-dimensional array of scintillation strips.
The experimental dependencies of the signal value versus position of optical
fiber with a diameter of 1 mm on the photocathode of the 20 anode PMT were also
measured. As a result of
processing the collected data, space resolution was obtained
at level of $\pm 0.7\ mm$, with a time resolution of
around $\pm 1.0\ ns $.

Speaker: Valeri Brekhovskikh (Institute for High Energy Physics of NRC Kurchatov Institute (R)

TheCoordinateSensitiveDetector.pdf

112 Timing techniques with picosecond-order accuracy for novel gaseous detectors

To meet the needs arising from the high-rate environments in current and future accelerators, detectors with high precision timing capabilities are of utmost importance. Dedicated R&D effort is carried out, resulting in novel detector technologies with excellent timing capabilities. Gaseous detectors instrumentation contributes to this effort and an example is the PICOSEC-Micromegas, which has demonstrated the ability to time 150GeV muons with 25ps timing resolution and photons beams (∼70p.e.) with 6.8ps.
However, during R&D phase, the full waveform is usually used for the extraction of the timing information from the signal, increasing the data amount and requiring expensive, energy-consuming and bulky fast oscilloscopes. Towards forward applications and large-scale detectors, front-end electronics are of paramount importance to undertake the data acquisition. For each detection technology data acquisition should retain the signal timing characteristics and consequently the timing resolution on the particle’s arrival time.
This work investigates the potential of timing techniques, alternative to the Constant Fraction Discrimination applied on the full digitised waveform, used in the data analysis of prototype detectors (i.e. for the PICOSEC Micromegas). More specifically, we investigate the adequacy of Time-over-Threshold timing technique using multiple constant thresholds, on experimental data. This method introduces a “time walk” that impinges on the timing resolution. We mitigate the effect of time walk using two different methods. In the first, the required correction is applied using the Time-over-Threshold value, while in the second approach the fraction of the area of the pulse that lies above the appropriately selected constant threshold value is used to parameterize the time walk correction. The results of this study prove the feasibility of the Time-over-Threshold timing technique using multiple thresholds for data acquisition and achieving resolution 10ths of picoseconds. We also demonstrate that similar results can be achieved using machine learning approaches.

Speaker: Maria Evanthia Tsopoulou

Tsiamis Angelos.pdf

113 Investigating machine learning solutions for a 256 channel TCSPC camera with sub-70 ps single photon timing per channel at data rates > 10 Gbps.

The development of a Time Correlated Single Photon Counting (TCSPC) camera with 256 channels has enabled several applications where single photon sensitivity is crucial, such as LiDAR, Fluorescent Lifetime IMaging (FLIM) and Quantum Information Systems. The microchannel plate-based Multi-Anode Photo-Multiplier Tube (MAPMT) is a 16 × 16 array of 1.656 mm pitch pixels with an active anode area of 26.5 × 26.5 mm$^2$. Each pixel can time single photons with an accuracy of 60 ps rms at a maximum photon rate of 480 KHz.
The timing electronics are capable of measuring 120 Mcps, producing huge volumes of data for processing, in the region of 10 Gbps per detector. Limitations in algorithmic data analysis techniques are critical for this application so in this paper we demonstrate a machine learning (ML) model which can determine the photon event coordinates with the objective of processing each one photon per ~10 µs. The model applies calibrations for the detector and electronics such as amplitude walk, and charge measurement and channel to channel threshold variation. Optimisation of the model is detailed within the paper, including training hyperparameters, the clustering of coincident events and compression of the model through pruning techniques.
The ML model is trained and tested on a simulation of the microchannel plate (MCP) PMT with timing electronics configured for use as a TCSPC camera, utilising charge sharing techniques to further improve the spatial resolution of the detector. We assess the performance of this approach compared to algorithmic approaches and introduce statistical reasoning of the robustness of the model. Further objectives of the research are to test the model on detector data, allowing assessment on the variance of accuracy between simulated and real data.

Speaker: Amelia Markfort (Photek)

114 Modelling the behaviour of microchannel plates using CST particle tracking software

Photon counting detectors are essential for many applications, including astronomy, medical imaging, nuclear and particle physics. An extremely important characteristic of photon counting detectors is the method of electron multiplication.

In vacuum tubes such as photomultiplier tubes (PMTs) and microchannel plates (MCPs), secondary electron emission (SEE) provides electron multiplication through an accelerating field across the dynode. A significant electron cascade, with time resolution in the 10s of picoseconds, can be observed in these structures and are routinely used in industry and research. Both devices have been thoroughly tested experimentally.

Developing new MCP designs can be expensive and time consuming so the ability to simulate new structures will provide many advantages to instrument designers and manufacturers. There are, however, significant challenges in accurately simulating MCPs with many geometrical variables to consider as well as material SEE properties. The SEE process is probabilistic, and with MCPs having a very high gain, significant computational resource is required to simulate the resulting electron output for a model.

In our research we illustrate how this can be achieved by developing a MCP model using Computer Simulation Technology (CST) software. The model consists of a charged particle source, a small seven-pore MCP structure (including electrodes, resistive and emissive surfaces), as well as the readout anode, with appropriate potentials applied to the components of the model.

We present simulation results from the modelled MCPs, demonstrate electron multiplication performance, and compare these results with those predicted by theory and observed experimentally. Our goal is to expand this model and identify optimum MCP parameters for various science applications using novel materials to optimise detector performance.

Speaker: Emily Baldwin (University of Leicester)

115 The transmission dynode (tynode) vacuum electron multiplier

With Atomic Layer Deposition (ALD) MEMS technology, thin multilayers have been realised which emit, after the absorption of an energetic electron at the top side, a multiple of secondary electrons at the bottom (emitting) side. In order to avoid charge-up effects, one of the layers has the function to replenish electrons and is therefore a conductor. With ALD MgO, a transmission secondary electron yield (TSEY) of 5.5 has been reached, enabling the single-electron sensitive Timed Photon Counter TipC in which a stack of 8 tynodes is placed on top of the TimePix3 or TimePix4 chip.
The alignment of 8 tynodes in a stack is obtained by applying grooves at both sides of a tynode: a glass wire in the groove is sandwiched between adjacent tynodes, locking their mutual 3D position.

Speaker: Harry Van Der Graaf (Nikhef National institute for subatomic physics (NL))

Harry van der Graaf.pdf

116 The second production of RSD at FBK

In this contribution we describe the second run of RSD (Resistive AC-Coupled Silicon Detectrors) designed by INFN Torino and produced by FBK, Trento.
RSD are $n$-in-$p$ detectors intended for 4D particle tracking based on the LGAD technology that get rid of any segmentation implant in order to achieve the 100% fill-factor. They are characterized by three key-elements, (i) a continuous gain implant, (ii) a resistive $n$-cathode and (iii) a dielectric coupling layer deposited on top, guaranteeing a good spatial reconstruction of the hit position while benefiting from the good timing properties of LGADs.
We will start from the very promising results of our RSD1 batch in terms of 4D-tracking and then we will move to the description of the design of the RSD2 run.
In particular, the principles driving the sensor design and the particular AC-electrode layout adopted to optimize the signal confinement will be addressed, also focusing our attention on other important detector figures-of-merit, such the role of substrate thickness, metal thickness and on the radiation-resistance properties.

Speaker: Marco Mandurrino (INFN)

117 Digital Trigger Module for Cherenkov Time of Flight Detector

The ATLAS Forward Proton (AFP) project extends the forward physics program of the multipurpose ATLAS detector located at LHC in CERN. The time-of-flight (ToF) detector measures the time delay of the detected high-energy protons (HEPs) during the multiple proton-proton collisions. Due to the high luminosity at LHC the number of events detected by ToF is enormous as well as the amount of data produced. The main purpose of the digital trigger module (DTM) is to select the events relevant to the ongoing physical experiment. The DTM input signals are compared with the remotely set logical conditions. Then the module decides whether the input signals will pass to the following chain of ToF detector or not. The secondary function of the device is to send the control commands to the data acquisition system which stores the data from the selected levels (modules) of the ToF chain. The DTM performs the high-speed signal processing of the signals with rate up to 40 MHz (bunch clock frequency). The selection of the relevant events takes approximately 9 ns. After the full testing procedure (including the test in DESY and at the CERN beam test facilities) the DTM will be installed at LHC.

Speaker: Jan Zich (University of West Bohemia (CZ))

Digital Trigger Module for Cherenkov Time of Flight Detector.pdf

118 Study of LGAD for Timing Measurements in ILC Detectors

The International Linear Collider (ILC) is an electron-positron collider planned to be constructed in Japan. The ILC detectors are designed with particle flow concept, which utilizes highly-granular calorimeters to separate showers in jets. We are studying to use Low Gain Avalanche Detectors (LGADs) for the sensitive layer of the electromagnetic calorimeter of ILC detectors. Timing resolution of a few 10 psec per hit, possible to be obtained with LGADs, enables particle identification of hadrons (pi/K/p separation) by Time-of-Flight method, and also improves shower clustering which is critical to the performance of particle flow. As the calorimeter application we need flat response over surface of multi-cell LGAD detectors. We are investigating possible usage of LGADs with gain layer at the opposite side of sensitive region, with which more uniform response than usual LGADs (with gain layer just below the readout electrodes) is expected. We will report the measurements with test sensors, including responses of charge and timing correlation with multiple sensors by penetrating positron beam.

Speaker: Mami Kuhara (Kyushu University)

poster_PSD_#208.pdf

119 The ATLAS Forward Proton Time-of-Flight detector: use and projected performance for LHC Run 3

The Time-of-Flight (ToF) detectors of the ATLAS Forward Proton (AFP) system are designed to measure the primary vertex z-position of the pp -> pXp processes by comparing the arrival times measured in the ToF of the two intact protons in the final state.

We present the results obtained from a performance study of the AFP ToF detector operation in 2017. A time resolutions of individual channels ranging between 20 ps and 40 ps are extracted, even though the AFP ToF efficiency is below 10%. The overall time resolution of each ToF detector is found to be 20(26) +- 4(5) ps for side A(C). This represents a superb time resolution for a detector operating at few milimeters from the LHC beams.

Events from ATLAS physics runs at moderate pile-up taken at the end of 2017 are selected with signals in ToF stations at both sides of ATLAS. The difference of the primary vertex z-position measured by ATLAS and the value obtained by the AFP ToFs is studied. The distribution of the time difference constitutes of a background component from combinatorics due to non-negligible pile-up, and significantly narrower signal component from events where protons from the same interaction are detected in ToF. The fits performed to the distribution of the reconstructed time difference yield the vertex position resolution (of about 6 mm +- 1 mm at best) that is in agreement with the expectation based on single-ToF channel resolutions.

Speaker: Tomas Komarek (Palacky University (CZ))

120 LGAD Development for the LHC’s High-Luminosity Upgrade

The need for 4D (fast timing in addition to 3D resolution in space) silicon particle detectors has become very apparent with the introduction of the High-Luminosity (HL) upgrade at the LHC. Timings on the order of tens of picoseconds will allow better reconstruction of the ~200 primary vertices along the beam line in every bunch crossing. Correct association of tracks with primary vertices is particularly difficult closer to the beam axis where the track density is greatest and reconstruction with 3D detectors alone is insufficient.
The University of Birmingham, University of Oxford, the Rutherford Appleton Laboratory, and the Open University are developing and testing new LGAD sensors. This project, aimed at developing Ultra-Fast Silicon Detectors (UFSD) of characteristics and performances suitable for use at HL-LHC High Granularity Timing Detector (HGTD), is being developed in collaboration with Teledyne e2v.
The first fabricated batch of 22 six-inch wafers, featuring 50 µm thick high resistivity epi layer with different gain layer implants was completed successfully.
We will present the LGAD design process and compare the results with Synopsys TCAD simulations. We will discuss I-V and C-V measurements across wafers for device sizes ranging between 1 mm, 2 mm, 4 mm and 2x2 arrays of 1 mm devices, and comparisons to PiN diodes where the gain layer is not present. Gain measurement using TCT laser injection on both PiN and LGAD individually packaged devices will be shown. Preliminary timing measurements and test results before and after proton irradiation will also be provided.

Speaker: Jonathan Mulvey (University of Birmingham)

Preliminary Test Results of LGADs from Teledyne e2v for the LHC’s High-Luminosity Upgrade​​.pdf

Applications in Life Sciences and Biology; Applications in Particle Physics 3

Conveners: Nigel Watson (University of Birmingham (GB)), Jon Lapington (University of Leicester)

121 (Some ) applications of the Medipix and Timepix ASICS in Life Sciences and Biology

Speaker: Michael Campbell (CERN)

MC_PSD2021_uploaded.pdf

MC_PSD2021_uploaded.pptx

122 Development of Compton-PET hybrid imaging system with CeBr3-SiPM arrays

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) has played an important role in nuclear medicine. While PET can only visualize a positron emitter by detecting annihilation gamma-rays, SPECT is used for low energy gamma-ray imaging (50-400 keV) by using a Pb-based collimator. It is difficult to integrate these modalities because SPECT requires collimators to determine the direction of incoming gamma-rays. Against this backdrop, we proposed a Compton-PET hybrid camera, which can provide images of PET and SPECT nuclides simultaneously by PET imaging and Compton imaging without any collimators. Recently, we succeeded the simultaneous in vivo imaging of $^{18}$F-FDG and $^{111}$In antibody with a GAGG- silicon photomultipliers (SiPM) based camera. In this study, we have developed a CeBr$_3$-SiPM based Compton-PET hybrid camera to improve time resolution potentially for time-of-flight PET imaging and evaluated the performance of PET imaging and Compton imaging.

The CeBr$_3$ scintillator has first decay time (20 ns), excellent light output (~70000 photons/MeV), and great energy resolution (~4%@662 keV when coupled with APD). The 8×8 arrays of CeBr$_3$ scintillator were fabricated by C&A corporation. The pixel size is 2.5 mm × 2.5 mm, and the pitch size is 3.2 mm. Each pixel was separated with the BaSO4 powder reflector. The arrays were hermetically sealed in an aluminum package with a quartz window and were coupled to 8×8 arrays of SiPMs (Hamamatsu MPPC S13361-3050). The charge signals from SiPMs were processed through time-over-threshold (ToT)-based application specific integrated circuits with the intrinsic time resolution of 50 ps. The time resolution of 198.7 ps was achieved with 1 mm thick CeBr$_3$ array detectors by using a digital oscilloscope. In addition, the angle resolution of a CeBr$_3$ Compton camera with the dynamic ToT method was 5.5° at 662 keV. In the presentation, we will report the evaluation in detail.

Speaker: Dr Mizuki Uenomachi (RIKEN)

presen_uenomachi.pdf

123 Design and assembly of a fibre-type heterostructured scintillator for Time of Flight Positron Emission Tomography (in-person)

Improving the performance of time of flight (ToF) positron emission tomography (PET) scintillators towards a coincidence time of 10 ps will enable real time imaging and a 16x increase in sensitivity [1], [2]. To achieve this both ultra-fast scintillation and short attenuation length are needed. Current monolithic inorganic scintillators are effective at capturing 511 keV gamma radiation but have decay times of 10s to 100’s of nanoseconds, whilst plastic or nanoparticle loaded plastic scintillators have fast decay times but lack the attenuation length to be effective PET scintillators. To bypass these limitations a heterostructured scintillator has been proposed [3] which synergistically combines a dense single crystal matrix with a fast scintillator component. Gamma capture occurs primarily in the matrix and energy shared with the fast component through recoil electrons, leading to fast scintillation and effective gamma capture in one volume.
Here we present the fiber-based heterostructure detector: a single crystal matrix enclosing fast scintillator fibres. The scientific and engineering challenges involved are complex, ranging from the optimisation of scintillation properties to pixel manufacture. Simulations were used to map the available parameter space and thus guide pixel design and material choice. An initial layout was chosen and Bismuth germanate (BGO) selected as the matrix material. Machining this hard, brittle material is non-trivial, but could be optimised. We patterned BGO slices with channels, before assembling them into a matrix. This was then filled with a vinyltoluene based polymer scintillator to form a prototype fibre-type heterostructure. Preliminary scintillation performance of the pixel prototype will be presented.
This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) grant EP/S013652/1 for Cranfield University. Part of the work was carried out in the framework of Crystal clear collaboration and supported by the CERN Budget for Knowledge Transfer to Medical Applications

Speaker: Edith Grace Rogers (Cranfield University)

heterostructures for ToF PET.pdf

heterostructures for ToF PET.pptx

124 phenoPET: A PET scanner for Plants based on digital SiPMs

The PET scanner phenoPET is a system dedicated for plant research developed and used for phenotyping studies at the Research Center in Jülich. The scintillation detectors use LYSO scintillator crystals of 1.85 × 1.85 × 10 mm$^3$ size (Crystal Photonics, Inc.) and digital Silicon Photomultipliers as photodetectors (Philips DPC). 4×4 crystals share 2×2 photodetector pixels at a time. Controlled light spreading guarantees clear identification of the individual crystals.
The whole scanner is equipped with more than 36000 crystals. Unlike to clinical PET scanners the detectors are arranged in a horizontally oriented ring which allows scanning of plants in an upright position. The field of view measures 18 cm in diameter and 20 cm height.
A recent revision of firm- and software resulted in an increased bandwidth of the data acquisition system, allowing dynamic studies of up to 120 MBq in the field of view. For the sensitivity in the center field of view we now obtain a value of 9.2% (ΔE=250-750keV).

Speaker: Matthias Streun (Forschungszentrum Jülich GmbH)

160_streun_PSD12_Birmingham2021.pdf

125 First test beam of an all-silicon polarimeter demonstrator for proton EDM searches (in-person)

Permanent EDM (Electric Dipole Moments) of elementary particles are prime candidates for finding new physics beyond the Standard Model. Permanent EDM of charged particles can be measured in innovative storage rings by observing a polarisation change caused by interaction between a particles spin vector and stable electric fields.
The cpEDM (charged particle EDM) Collaboration aims to design an all-electric storage ring for proton EDM studies that could be either hosted at CERN or COSY (Cooler Synchrotron). To address this challenging project, the cpEDM Collaboration assumes a staged approach. The prototype ring stage, which serves as a proof-of-principle, uses protons with 30-45 MeV kinetic energy necessitating a low material budget polarimeter.
This contribution presents an all-silicon polarimeter for proton EDM searches. The polarimeter is comprised of one 100 µm layer of HV-CMOS (High Voltage-CMOS) sensors for high spatial resolution, surrounded by two layers of LGAD (Low Gain Avalanche Detectors) in a time of flight configuration to provide high energy resolution by means of picosecond timing resolution. The HV-CMOS layers will be used to accurately determine the scattered direction of the protons and for track reconstruction. Geant4 simulations have showed that such a system meets the energy resolution necessary for the experiment (less than 3%) whilst retaining a short time of flight length (less than 1 m).
We have designed a polarimeter demonstrator based on a prototype LGAD (USFD2), with 200 μm strip pitch. The polarimeter is read out using a TRB3 board featuring four FPGA-based TDCs (Time-to-Digital Converters) with <20 ps RMS (Root Mean Square) time precision between two individual channels. The positions of the timing layers can be reconfigured remotely to test the energy resolution obtained with different time of flight lengths. The application for pEDM studies, design and test beam evaluation at a medical proton therapy centre are presented.

Speaker: James William Gooding (University of Liverpool (GB))

LGAD_PSD_2021.pdf

10:30 Coffee/Tea

Poster Session 5 (Gas-based Detectors; Medical Applications of Position Sensitive Detectors)

Gas-based Detectors
Medical Applications of Position Sensitive Detectors

Conveners: Konstantinos Nikolopoulos (University of Birmingham (GB)), Tony Price (University of Birmingham (GB))

126 Upgrade of the ATLAS Muon Spectrometer with high-resolution Drift Tube Chambers (sMDT) for LHC Run-3

The Monitored Drift Tube detector technology is used in the ATLAS experiment for the very accurate, reliable muon tracking and momentum measurements in the barrel and endcap regions. Already in Run 2 of the LHC they had to cope with very high background counting rates up to 500 $Hz/cm^2$ in the inner endcap layer. At High-Luminosity LHC, the background rates are expected to increase by almost a factor of 10. New small (15 mm) diameter Muon Drift Tube detectors have been developed in the Max Planck Institute for Physics in Munich for the upcoming upgrade of the ATLAS muon spectrometer. New chambers will provide about an order of magnitude higher rate capability and allow for the installation of additional thin gap RPC trigger technology in the transition region ($1.0<|\eta|<1.3$) of the ATLAS muon system for HL-LHC runs. A smaller size project, known as BIS78 (Barrel Inner Small sectors), is developed with a foreseen installation during the LHC Long Shutdown 2 (2019-2021). This pilot project will reinforce the fake muon rejection and the selectivity of the muon trigger in the problematic transition region by adding new BIS78 muon stations which are composed of 16 sMDT chambers with 32 RPC triplets (BIS7 and BIS8). In this contribution, we will describe the new BIS78 sMDT detector design, the quality assurance and certification path, as well as will present the overview of the chamber’s validation and installation, their cavern commissioning status and performance in the ATLAS combined runs during Milestone weeks.

Speaker: Elena Voevodina (Max-Planck-Institut fur Physik (DE))

Voevodina_PSD12_Poster_12-17Sept2021-V9.pdf

127 Precision tracking micro-pattern gaseous detectors at Budker INP

Micro-pattern gaseous detectors (MPGDs) can operate at very high particle flux demonstrating consistently high efficiency and coordinate resolution in tens microns scale. Tracking MPGDs are developed and applied in several experiments at Budker INP.
Eight two-coordinate cascaded Gas Electron Multiplier based detectors (GEM-detectors) have been working at the Tagging System of KEDR experiment (TS KEDR) at VEPP-4M electron-positron collider since 2010. TS KEDR is dedicated to two-photon physics.
Three triple-GEM-detectors are integrated into Photon Tagging System of the DEUTERON facility at VEPP-3 storage ring. Strip pitch of the readout structure is 500 um and the spatial resolution was measured to be less than 50 um. The material budget of each detector is low - about 0.3% of radiation length, which suppresses multiple scattering.
Triple-GEM detectors having orthogonal strips with a pitch of 250 um and low material budget were assembled for the Test Beam Facility and demonstrated excellent efficiency above 99% and spatial resolution better than 50 um.
Cascaded GEM-detector with pad readout has been mounted for the laser polarimeter for precise energy measurements at VEPP-4M collider.
MPGD is proposed for upgraded tracking system of the CMD-3 detector at VEPP-2000 collider. The upgraded system will include a new cylinder tracking and trigger detector as well as two end-cap discs. Micro-RWELL technology is used for the upgrade. The first two end-cap discs are assembled and results of the first tests will be reported.
The cylindrical detector and end-cap discs for CMD-3 are considered as the prototypes for the Inner Tracker of future Super Charm-Tau Factory. Compact Time Projection Chamber (TPC) is considered as one of the options for the Inner Tracker with the readout detector based on MPGD technology. The prototype of the TPC is being assembled and the first tests with the prototypes of the readout plane will follow soon.

Speaker: Timofei Maltsev (Budker Institute of Nuclear Physics (RU))

BINP-GEM-PSD-2021 poster.pdf

128 Novel Thin-Scintillator Ion Beam Imagers

The thin-scintillator ion beam imager (SIBI) is a novel charged particle imaging detector developed by our group for various applications. It uses proprietary high light-yield, very thin (<500 µm) hybrid inorganic scintillator sheets or ultra-thin (3-200 µm) organic scintillator films. The scintillation elements are coupled by low f-number optics to high sensitivity, low-noise or ultra-low noise machine vision cameras. The initial application is for beam imaging and profile analysis at the U.S. DOE Facility for Rare Isotope Beams (FRIB) and other ion beam laboratories. For FRIB, we are developing the SIBI towards maximizing sensitivity to low rate and low energy ion beams with real-time feedback while limiting beam degradation for moderate energy FRIB beams over a large dynamic range from single particles up to ~10^10 pps. The SIBI has demonstrated detection sensitivity to single 5 MeV alpha particles with a position resolution of 5 µm, while for heavier ions, the position resolution is ~2 µm. Other SIBI applications are being developed for conventional proton/ion beam therapy and for the newly emerging cancer treatment modality known as FLASH radiotherapy (RT), which delivers approximately four (4) orders-of-magnitude higher dose rates than conventional RT. The SIBI is intended to provide dosimetric and imaging capabilities necessary for FLASH-RT clinical trials to proceed. We will describe system designs and report preliminary performance results.

Speaker: Dr Peter Friedman (Integrated Sensors, LLC)

PSD12_Poster_v2.0_Peter_Friedman.pdf

129 Proton-range verification in proton radiation therapy using PET

We will report first performance results for a prototype PET system designed for proton rage verification in proton therapy. This prototype will later be evaluated with phantoms and animals at the proton therapy center of MD Anderson Cancer Centre in Houston, Texas, USA.
The PET system consists of two detector module assemblies in the shape of angular sections of a cylinder with an inner diameter of 325 mm and axial length 105 mm. The two angular sections cover 99 degrees each. Because of the partial angular coverage, optimization the time resolution is essential in this application. Each PET detector module consists of an 8x8 LYSO array with 3x3x15 mm3 pixels in one-to-one coupling to one Hamamatsu MPPC array S14161-3050HS-08 with 3x3 mm2 pixels. The readout electronics is developed by PETsys Electronics and is based on the PETsys TOFPET2 ASIC. The complete PET system will has 96 detector modules and 6144 electronic readout channels. The interface to the DAQ computer is based on a DAQ module using the PXI express bus, and receiving data from the front-end part through two optical links at 6 Gbit/s.
A Clock&Trigger module located near the detectors will distribute clock signals and allow selecting system wide coincidence events selection in the front end firmware. The complete readout can be divided in a configurable number of trigger regions, and events without a coincidence partner in a different trigger region will not be transmitted to the DAQ computer. This will reduce the data rate to the computer by about one order of magnitude.
We will also report the results of a study of radiation damage to the detectors in this application. The study is based on Geant4 simulation.

Speaker: Mr Kyle Klein (Department of Physics University of Texas at Austin Austin, TX 78712, USA)

130 Random and scatter noise reduction in PET imaging using entangled annihilation gamma photons with Compton PET pixel detectors

Reduction of random and scatter events contributing to the background on the reconstructed image is important in PET imaging. Two gamma rays from annihilation of para-positronium containing anti-parallel spins are entangled and have orthogonal linear polarization. The orthogonal linear polarization in two correlated photons results in the difference between azimuthal scattering angles of two photons tend to be 90˚. Its correlation shows larger amplitude at polar scattering angle near 81˚. Non correlated photons will show no preferred azimuthal angle difference when one of the photons is scattered before reaching detectors or two photons are not originated from the same annihilation event. In the experiment we take coincidence events from double Compton scattering whose azimuthal angle difference is near 90˚ to get larger proportion of true signals with reduced random and scatter events.
Experiment was conducted to characterize the distribution of azimuthal angle differences in double Compton scattering events with pixelated Ce:GAGG-SiPM detectors forming Compton PET scanner. Octagon shaped 8 arrays were used for the experiment. Measured azimuthal angle indicates strong difference intensity at around 90˚ and low intensity at 0˚ and 180˚ as expected from the theory. These correlations can be applied to the reduction of scatter and random coincidence events and the improvement in PET imaging will be reported.

Speaker: Donghwan Kim (University of Tokyo)

131 Detection module based on position-sensitive large-area Silicon photomultipliers

Silicon Photomultipliers are compact single-photon-sensitive detectors, widely used in many applications. In FBK (Trento, Italy) we developed large area SiPMs (up to 10x10$mm^2$), based on different technologies and we are also focusing on the position-sensitive SiPM (PS-SiPM) technology based on charge-sharing approach. These are based on the so called “linearly-graded, LG” technology, exploiting a weighted current dividers on vertical and horizontal axis, to obtain signals (left, right, top and bottom signals) with amplitude and charge proportional to the light-absorption position.
Such large area detector with position sensitivity is very interesting in applications like ultra-high spatial resolution, MR-compatible PET and in the creation of a compact gamma and beta cameras with a reduced number of channels, for radio-guided surgery or other clinical decision support tool for diagnostic imaging.
In this contribution, we illustrate the project developed in collaboration with the University of Geneva for a detection module based on a 2×2 tile of large-area PS-SiPMs, including front-end amplifiers and shaped like a “handable” probe. Total area is 1.6x1.6 $cm^2$. The PS-SiPMs are connected in a smart configuration, maintaining a very low number of channels. Indeed, while for a single LG-SiPM there are 4 output, for a 2×2 tile, we have just 6 outputs. The measured position resolution (measured with a pulsed LED, scanned over active area) is better than 0.5 mm.
Finally, we performed an estimation of the performance of such module when used as a gamma camera for tumor detection. With OpenGate simulation, we proved that for a radio-tracer emitting gamma of lower energy, as 99mTc, the gamma camera could achieve an excellent performance. Superficial tumors, of about 2 mm, could be well reconstructed in less than 20 seconds. Tumors bigger than 6 mm in radius could be detected at 30 mm deep within about 10 seconds.

Speaker: Dr Fabio Acerbi (Fondazione Bruno Kessler (FBK))

Poster_Acerbi_POSICS_(PSD12).pdf

132 The development and evaluation of Compton camera (Gri+) for medical imaging applications

To improve medical treatment, the medical imaging field needs to develop more accurate imaging modalities. Using a Compton camera that has the ability to image a wide energy gamma-ray, has a wide field of view with a good angular resolution and electronically collimated, could help to improve medical treatments. To investigate physiological bodily functions, nuclear medicine imaging uses a low-energy gamma-ray, which is emitted from radiotracers. The distribution of the radiotracer material in the body is commonly imaged using a single-photon emission computed tomography (SPECT) system. However, SPECT systems are inherently limited in terms of their spatial resolution and sensitivity. This is due to SPECT systems being scintillation detection systems equipped with a mechanical collimator. Furthermore, imaging the prompt gamma-ray (up to 10MeV) during proton therapy has emerged as a real-time technique for verifying and monitoring the dose delivered.
The University of Liverpool has developed a Compton camera imaging system (Gri+) consisting of two position-sensitive semiconductor detectors and one coaxial detector; this imaging system is electronically collimated. The double-sided Si(Li) planar strip serves as a scatter detector with 13 orthogonal strips on each side. This detector has a sensitive position resolution of 5x5x8 mm3. Additionally, the HPGe double-sided planar strip serves as an absorber detector. This detector has 12 orthogonal strips on each side with a sensitive position resolution of 5x5x20 mm3. The coaxial HPGe serves as an additional absorber for high energy gamma-rays.
The current study evaluates method used by the Gri+ system and its ability to image a range of gamma-ray energies, commonly used in medical applications. Two point-like sources of 166 keV (139Ce) and 1.8 MeV (88Y) and medical phantom were used to evaluate the system performance and the Gri+ imaging ability. Further analyses are in progress to investigate a higher energy gamma-ray such as 4.4 MeV.

Speaker: Hamed Alshammari (University of Liverpool)

133 Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

The instantaneous luminosity of the Large Hadron Collider at CERN will be increased by about a factor of five with respect to the design value by undergoing an extensive upgrade program over the coming decade. The largest phase-1 upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the New Small Wheels (NSWs) during the long-LHC shutdown in 2019-2021. Along with Micromegas, the NSWs will be equipped with eight layers of small-strip thin gap chambers (sTGC) arranged in multilayers of two quadruplets, for a total active surface of more than 2500 m$^2$. To retain the good precision tracking and trigger capabilities in the high background environment of the high luminosity LHC, each sTGC plane must achieve a spatial resolution better than 100 μm to allow the Level-1 trigger track segments to be reconstructed with an angular resolution of approximately 1mrad. The sTGC structure consists of a grid of gold-plated tungsten wires sandwiched between two resistive cathode planes at a small distance from the wire plane. The precision cathode plane has strips with a 3.2mm pitch for precision readout and the cathode plane on the other side has pads for triggering. The sTGC design, performance, construction and integration status will be discussed, along with results from tests of the chambers with beams, cosmic rays and high-intensity radiation sources. The status of commissioning the sTGC for ATLAS installation will also be updated

Speaker: Xinfei Huang (University of Michigan)

Xinfei_ATL_PSD12.pdf

134 CMS Improved Resistive Plate Chamber Studies in Preparation for the High Luminosity Phase of the LHC

The high luminosity expected from the HL-LHC will provide a great opportunity for precise physics measurements and searches for new physics. Nevertheless, the increased rate of particles coming from the collisions will pose a challenge for the CMS detectors.
To prepare the muon system for the challenging conditions during the high luminosity phase, several upgrades have been planned and are being developed. Thanks to their fast time and space resolution, the Resistive Plate Chambers form part of the trigger system and are installed both in the barrel and endcap regions as a subsystem of the muon detector.
As part of the upgrades, the muon forward region will be enhanced with two stations, called RE3/1 and RE4/1, equipped with improved Resistive Plate Chambers (iRPCs). These detectors use thinner electrodes, a narrower gas gap (1.4 mm compared to 2 mm in the current design) and improved front-end electronics. These features allow them to withstand particle rates up to few $kHz/cm^2$. Furthermore, they will extend the geometrical acceptance of the RPCs from a pseudorapidity of 1.9 to 2.4. In this work we present different studies related to the iRPC prototypes in preparation for the high luminosity phase of the LHC.

Speaker: Cecilia Uribe Estrada (Autonomous University of Puebla (MX))

PSD12Poster2021_C_Uribe_Estrada.pdf

135 First results of an oncological brachytherary fiber dosimeter

The ORIGIN project aims to deliver photonics-enabled, adaptive, and more effective diagnostics-driven brachytherapy for cancer treatment through advanced real-time radiation dose imaging and radioactive source localization. This goal will be achieved by developing a 16 to 32 optical-fiber-based system where scintillating light is detected by Silicon Photomultiplier. This work reports the results achieved in laboratory and hospital conditions with single-sensor prototypes for low and high dose rate brachytherapy, requiring different specifications. The former requires high sensitivity and low minimum detectable signal, whereas an extended linearity range is crucial for the latter. Laboratory activities were essential to identify the optimal silicon photomultiplier. Preliminary tests, performed at the hospital premises for both treatments, assessed the viability of the proposed solution. The first results were also relevant to identify the ASIC-based readout system that will allow the project to reach the final goal of engineering a multi-fiber real-time dosimetry imager.

Speaker: Agnese Giaz (Università degli studi dell'Insubria)

PosterPSD_Giaz.pdf

136 Bergen proton-CT project

Proton therapy is a treatment method that utilizes the energy deposition of heavy ions to concentrate the dose delivered to a patient during the treatment of the malignant tumor. The Bergen proton Computed Tomography (pCT) collaboration is constructing a prototype detector capable of both tracking and measuring the energy deposition of ions in order to minimize uncertainty in proton treatment planning.

The pCT detector designed by the Bergen pCT collaboration is a high granularity digital tracking calorimeter, where the first two layers will be used to obtain positional information of the incoming particle and act as tracking layers. The remainder of the detector will act as a calorimeter. The tracking layers will utilize a carrier made of ~200 µm thick carbon fleece, this is to minimize scattering effects. The calorimeter part of the detector will have the sensor chips mounted on aluminum carriers, there will also be a 3.5 mm aluminum layer in between each sensitive layer, which will act as absorber material. Each sensitive layer will be populated by 108 ALPIDE chip sensors, situated in a 12x9 grid to cover the entire 27 cm x 16.6 cm area of the detector. The ALPIDE chip was developed for the ITS2 upgrade at CERN and is a monolithic active pixel sensor manufactured using the 180 nm CMOS Imaging Sensor process by Tower Semiconductor. Each ALPIDE has a surface area of 30 mm x 15 mm and consists of a pixel-matrix with 512x1024 pixels.

This presentation will discuss the implementation of the design, present data taken with high-energetic (50-220 MeV/u) proton and ion beams at the Heidelberg Ion-Beam Therapy Center (HIT) in Germany, and present selected results from simulations.

Speaker: Viljar Nilsen Eikeland (University of Bergen (NO))

poster_PSD12_final (1).pdf

137 Position reconstruction studies with GEM detectors and the charge-sensitive VMM3a ASIC

Gas Electron Multiplier (GEM) detectors are a prominent example of Micro-Pattern Gaseous Detectors (MPGDs). One of their main features is that they provide a good spatial resolution over large areas (square metre sized detector modules). When the interacting particle deposits energy inside the detector volume, primary electrons are created that drift towards the readout anode (here: 9 mm drift distance). During the drift, the electron cloud diffuses (sigma of 250 µm) over fine pitch granularity readout electrodes (here strips with 400 µm pitch). With such granularities, spatial resolutions of about 100 µm are achieved. Due to the charge spread over several readout electrodes, even better spatial resolutions can be achieved (around 40 µm with high-energy MIPs in COMPASS-like GEM detectors) by using position reconstruction algorithms, like for example the centre-of-gravity (COG) method.

To apply the COG method, multi-channel charge-sensitive readout electronics is needed. For the here presented studies, the VMM3a ASIC was used, which will be briefly introduced. It records the charge information and allows a self-triggered high-rate, position and energy-sensitive readout of large area particle detectors.

Due to the discretised readout structure, a bias is introduced in the reconstructed position, which was similarly observed with Multi-Wire Proportional Chambers (MWPCs), indicating that a pure usage of the COG method may not be the optimal choice. In this presentation, a simple modification of the COG method to mitigate the bias effect is shown and its applicability is discussed. Further, a hardware feature of the VMM3a is presented, which allows to recover otherwise lost charge information in its threshold-based self-triggered readout scheme and thus improves the position reconstruction.

Speaker: Lucian Scharenberg (CERN, University of Bonn (DE))

poster_psd12_lucian-scharenberg.pdf

138 A slice-test demonstrator for the upgrade of the CMS Drift Tubes at High-Luminosity LHC

Drift Tubes (DT) detectors equip the CMS muon system barrel region serving both as offline tracking and triggering devices. Existing DT chambers will operate throughout High-Luminosity LHC, but, in order to withstand event rates and integrated doses far beyond the initial design specification, an upgrade of the current readout and trigger electronics is planned. In the upgraded system, time-to-digital converters (TDCs) will stream hits to new back-end boards that, beyond event matching, will perform online tracking of trigger segments exploiting the ultimate DT cell resolution. During the second LHC long shutdown, prototypes of the aforementioned electronics were installed in four DT chambers with the same azimuthal acceptance, instrumenting a demonstrator of the HL-LHC DT upgrade (DT slice-test). In this report, the motivation for such an upgrade will be highlighted, and the status of the DT slice-test operation, as well as its performance measured with cosmic-ray events, will be presented. Plans towards future developments of the demonstrator throughout Run-3 will also be discussed.

Speaker: Carlo Battilana (Universita e INFN, Bologna (IT))

PSD12_Battilana_DT_SliceTest.pdf

139 Panel TOF-PET imager

Positron emission tomography (PET) is one of the most important diagnostic tools in medicine, providing three-dimensional imaging of functional processes in the body. The method is based on detecting two gamma rays originating from the point of annihilation of the positron emitted being by radio-labelled agent, and used to follow the human's physiological processes. In Time-Of-Flight PET gamma rays' arrival time is measured in addition to their position. The coincidence timing resolution (CTR) of state-of-the art scanners is between 200 ps and 500 ps FWHM, which can already significantly improve the contrast in imaging large objects. To increase the sensitivity of the next-generation PET scanners timing accuracy should be substantially increased. By using latest advances multichannel system with improved CTR is becoming technologically possible. Generally 3D images from limited angle PET scanners are distorted and have artefacts. Fortunately, with improving timing resolution of PET gamma detectors, artefact free images can be obtained even by a very simplified detector. In the contribution we will show the simulation studies of the simple panel detector using gamma detectors with 50 ps coincidence timing resolution. With this new concept, the price of PET scanners for imaging single or multiple organs can be drastically decreased. We evaluated different panel detector arrangements by imaging different phantoms. We compared the reconstructed images with the image obtained with the Siemens Biograph Vision, state-of-the-art clinical PET scanner. We found comparable image quality parameters of both systems when the CTR approaches 50ps FWHM and also that good CTR can partially compensate for smaller gamma detection efficiency.

Speaker: Rok Pestotnik (Jozef Stefan Institute (SI))

psd12-Pestotnik.pdf

140 Recent advances in MicroScint beam profiler technology

This work illustrates some recent advances based on the so-called MicroScint, a technology developed by CERN and EPFL in recent years aimed to realize a beam transverse profiler with high spatial resolution based on a microfluidic device, obtained by a standard Silicon microfabricated structure filled with an organic liquid scintillator. The signals at each channel’s segments end are readout by a photodiodes array interfaced with a microcontroller. The Silicon microfabrication allows improving the detector spatial resolution (up to ~30 $\mu$m in this work) with respect to commercial scintillating fiber-based devices, limited to the minimum available size of 250 $\mu$m. Different MicroScint geometries have been fabricated and are described in this paper, together with preliminary experimental results obtained with UV light at 260 nm. In the perspective to obtain a more robust and easy-to-fabricate detector, the paper also presents the development of scintillating resin-based devices, obtained through PDMS moulds. The new design achieves a spatial resolution of ~15 $\mu$m. The same readout and characterization setup of the microfluidic devices has been used on these prototypes. Substituting the scintillating liquid with the resin opens up the possibility to 3D-print the active area of the scintillating devices without using any costly process. The developed detectors are designed to suit all types of proton or heavy ion accelerators, namely cyclotrons, synchrotrons, and linacs for beams starting from tens of MeV, DC or pulsed. In particular the simulations focused on a proton-therapy beam with typical intensity of 1.5e9 protons/s. The presented beam detectors could also be used for dosimetry, X-ray imaging or for fundamental physics experiments such as the generation of vortex beams and more generally for providing a novel diagnostic tool for experiments aimed at manipulating the wavefunction of fundamental particles.

Speakers: Michele Caldara (EPFL), Veronica Leccese (EPFL)

Microscint_PSD12.pdf

141 Longevity Study on the CMS Resistive Plate Chambers for HL-LHC

The CMS Resistive Plate Chambers (RPC) system has been certified for 10 years of LHC operation. In the next years, during the High luminosity LHC (HL-LHC) phase, the LHC instantaneous luminosity will increase to factor five more than the nominal LHC luminosity. This will subject the present CMS RPC system to high background rates and operating conditions much higher with respect those for which the detectors have been designed. Those conditions could affect the detector properties and introduce a non-recoverable aging effects. A dedicated longevity test is set up in the CERN Gamma Irradiation Facility (GIF++) to study if the present RPC detectors can survive the hard background conditions during the HL-LHC running period.
During the irradiation test, the RPC detectors are exposed to a high gamma radiation for a long period and the detector main parameters are monitored as a function of the integrated charge. The results of the irradiation test after having collected a sufficient amount of the expected integrated charge will be presented.

Speaker: Reham Aly (Bari University - Italy)

RPC_Longevity_PSD12_Reham.pdf

142 Towards 2D Dosimetry using Monolithic Active Pixel Sensors and a Copper Grating

Higher energy and intensity X-ray radiotherapy treatments are coming into wider use, having the benefit of requiring fewer treatment fractions and fewer hospital visits per patient. However, small percentage errors in MLC positioning and dose become bigger problems with higher doses per fraction. Hence, real-time treatment verification becomes essential. Where devices downstream from the patient suffer from scattering in the patient, upstream devices can disturb the therapeutic beam. Here, a method is proposed for performing dosimetry using Monolithic Active Pixel Sensors, which can be made thin enough to disturb the beam by <1%. To calculate the dose to the tumour, a verification device needs to make a measurement of the photon field. Some photons will Compton scatter an electron in the silicon and generate a signal. However, this signal is obscured by energy deposits from contamination electrons, originating from Compton scattering in the accelerator head and air. Often extensive build-up material is added to verification devices to reduce the electron contamination and enhance the photon signal. However, this leads to degradation of the beam intensity to the patient. Instead we propose using thin strips of 50 um thick copper in a grating pattern and measuring the difference in the signal with and without it. The contamination electrons are relatively undisturbed by the presence of the thin copper strips and the photon signal generated via Compton scattering is enhanced. Hence the difference in the two signals mostly consists of energy deposits originating from the therapeutic photons. From this the dose to the patient can be derived. Using this technique, we show that the electron contamination signal can be reduced from 38% of the total signal to 2.6%. This allows to extract the photon signal only from the data and thus the dose to patient with a very thin upstream detector.

Speaker: Lana Beck (University of Bristol)

143 Pixelated silicon detectors for the measurement of small radiation fields in proton therapy

Advanced imaging and treatment techniques in proton therapy allow conformal high dose irradiation of the target volume with high precision using pencil beam scanning or beam shaping apertures. These irradiation methods increasingly include small radiation fields with large dose gradients at the edges, which require the development of new micro dosimetry systems with precise spatial resolution and small sensitive volume for quality assurance.
Based on their good spatial resolution and high rate compatibility, pixelated silicon detectors could meet the new requirements.
To assess their usability for micro dosimetry in proton therapy, as well as to determine the absolute proton flux, ATLAS Pixel detectors with Silicon sensors are used to measure transverse beam profiles of different irradiation modes at WPE in Essen, Germany.

The aim is to compare these with the expected expansions and to draw conclusions about the dose gradient at the field edges.
The possibility of determining the proton flux as well as the energy distribution of the irradiation fields with pixelated silicon sensors shall be evaluated under consideration of the characterizing results.

Speaker: Jens Weingarten (Technische Universitaet Dortmund (DE))

poster_PSD.pdf

144 A hybrid deep-learning framework based on the Wasserstein-GAN with non-subsampled contourlet transform for noise reduction in low-dose CT

Low-dose CT (LDCT) usually reduces the dose by reducing tube current compared to the normal dose CT (NDCT), and this behavior is affected by lowering the signal-to-noise ratio (SNR), resulting in poor image quality. LDCT has negative characteristic of different noises (e.g., photon noise, electronic noise, anatomical noise, etc.). Because the image quality of low-dose CT is dominated by noise, iterative reconstruction and image processing methods have been investigated. However, these methods are still challenging. Recently, the deep-learning based noise reduction results outperform the image performance of existing methods. In this study, as an alternative approach, we propose a hybrid deep-learning framework based on the Wasserstein-GAN (WGAN) with non-subsampled contourlet transform (NSCT) for enhanced noise reduction in low-dose CT. We trained the data separately with low- and high-frequency sub-bands using the NSCT. Our results indicated that the image characteristics of the noised reduction images were nearly close to that of the NDCT images, preserving superior image features and anatomical structures. Its effectiveness was validated by comparing image performance to those from other network methods such as CNN-MSE, WGAN-VGG for LDCT noise reduction. NSCT approach is useful for the dimensionality reduction for training and its strategy was optimized by means of separation of the frequency bands for various noise components in training

Speaker: Woosung Kim (yonsei university)

145 ACHINOS: A multi-anode read-out for position reconstruction and tracking with spherical proportional counters

The spherical proportional counter is a versatile gaseous detector with physics applications ranging from rare event searches to fast neutron spectroscopy. In its simplest form, the detector operates with a single channel readout and uses pulse-shape information to reconstruct the interaction radius, which is used for background discrimination and fiducialisation. Recent developments in the read-out instrumentation have enabled the use of a multi-anode read-out structure, ACHINOS. The multiple anodes provide information about the interaction position that, coupled with the radial information, can be used to reconstruct an ionisation track. This ability has implications for several applications of the detector, for example, background discrimination in rare event searches. Developments in the experimental implementation of ACHINOS will be discussed, along with simulations of the track reconstruction capability using a dedicated simulation framework.

Speaker: Dr Patrick Ryan Knights (University of Birmingham)

146 Improvement of three-material decomposition in spectral mammography using non-local means denoising

The accurate analysis of breast imaging is important because it has been reported that an increase in breast density of only 1% results in a 2% increase in the relative risk of breast cancer. The proteins, water, and lipids that determine breast density are important biomarkers in the diagnosis of breast cancer. In mammography, photon-counting detectors (PCDs) with energy-discrimination capabilities can cause errors in the measurement of chemical composition when the attenuation coefficient is small. This is typically the case with proteins, water, and lipids because of the low photon efficiency in each bin. In this study, a dual-energy technique for PCDs was developed based on a non-local means denoising technique for accurate material decomposition and the quantification of protein, water, and lipid content. To evaluate the proposed material decomposition algorithm, spectral images were acquired with a modeled PCD using the Geant4 Application for Tomographic Emission (GATE) version 6.0. Linear, quadratic, and rational models were used for three-material decomposition based on the spectral images acquired using the PCD. The proposed algorithm yielded the best results for the estimation of breast density, composed of three materials. It was determined that the developed approach improved the accuracy of three-material decomposition using a PCD with energy-discrimination capabilities. The presented material decomposition algorithm has the potential to improve the diagnostic accuracy of breast cancer detection based on the quantitative measurement of breast density using PCDs.

Speaker: Minjae Lee (Yonsei University)

147 Novel zigzag and diamond pattern for Micromegas and Gas-based detector

Gas-based detectors Micromegas are used in many high energy physics experiments to track charged particles. They can cover large areas with homogeneous gain, providing spatial resolution from millimeter to tenth of millimeter.
Micromegas can be read along one projection with strips (1D) or two projections with pads interconnected (2D), but the resolution highly depend of the density (pitch) of the pattern.
In the worse case, a particle hit a single pattern providing a resolution of pitch/$\sqrt{12}$.
To reduce this dependency, novel "zigzag" 1D pattern and "diamond" 2D pattern are tested and optimized to obtain the best resolution regardless of the pitch, in the context of the Electron-Ion Collider R&D on detectors.

Tested using a proton beam at Fermilab Test Beam Facility, zigzag and diamond geometries have been successfully characterized with Micromegas, showing $150\mu m$ 1D spatial resolution with a pitch of 2$mm$.
Identical readout have been tested with other gaseous detectors ($\mu$RWell, GEM) for a complete comparison. For Micromegas, the zigzag pattern have been tested on a full scale prototype of 40x40$cm^2$ with a pitch from 1 to 3$mm$.

In this presentation, it will be shown that zigzag and diamond patterns are efficient geometry for Micromegas and other gaseous detectors, compatible with future large detectors. Details on the characterization, detectors and technologies used will be discussed.

Speaker: Maxence Revolle (CEA)

148 Gas electron tracking detector for beta decay experiments

For 3D-tracking and identification of low-energy electrons a new type of gas-based detector was designed that minimizes scattering and energy loss.The current version of the detector is a combination of a plastic scintillator,serving as a trigger source,and a hexagonally structured multi-wire drift chamber(MWDC),filled with a mixture of helium and isobutane gas.The drift time information is used to track particles in the plane perpendicular to the wires,while a charge division technique provides spatial information along the wires.The gas tracker was successfully used in the miniBETA project as a beta spectrometer for the measurement of weak magnetism form factor in nuclear beta decay.The precision of the three-dimensional electron tracking,in combination with low-mass,low-Z materials and monitoring of backscattering from the electron energy detector,facilitated a reduction of the main systematics effects.

In the talk the results of the detector characterization will be presented.These results originate from performance studies with cosmic muons and low-energy electrons (<2 MeV) conducted for several pressures (300–700 mbar) and isobutane add-mixture percentages (10–50%).At certain conditions,a spatial resolution better than 0.5 mm was obtained in the plane perpendicular to the wires,while resolutions of 4–8 mm were recorded along wires.Thanks to precise tracking information,it is possible to eliminate electrons and other particles not originating from the desired decay with high efficiency.Additionally,using the coincidence between MWDC and trigger,background from gamma emission typically accompanying radioactive decays,was highly suppressed.An overview of the possible types of detector events will be provided together with the tracker’s ability to correctly recognize them.The latter was done by Monte Carlo simulations with Geant4 and Garfield++.Finally,the preliminary results from the beta spectrum study will be reported as well.

The presented experimental technique is also applied to the beta decay correlation experiment for tracking of electrons in neutron beta decay (BRAND project).Furthermore,it could be implemented for cloud size monitoring in ion traps.

Speaker: Dagmara Rozpedzik (Jagiellonian University)

PSD2021_poster_drozpedzik.pdf

Applications in Condensed Matter; Position Sensitive Fast Timing Detectors 2

Conveners: Dhiren Kataria (Mullard Space Science Laboratory, University College London), Nigel Watson (University of Birmingham (GB))

149 X-ray detectors at the Diamond Light Source, evolution and future challenges (in-person)

Speaker: Dr Nicola Tartoni (Diamond)

Nicola Tartoni key note.pptx

150 Development of a single-photon imaging detector with pixelated anode and integrated digital readout

We present the development of a single-photon detector and the connected read-out electronics.
This `hybrid' detector is based on a vacuum tube, transmission photocathode, microchannel plate and a pixelated CMOS read-out anode encapsulating the analog and digital-front end electronics.
This assembly will be capable of detecting up to $10^9$ photons per second with simultaneous measurement of position and time.

A microchannel plate with $5$-$10~\mathrm{\mu m}$ pore spacing, operated at low gain and treated with atomic layer deposition, was chosen to allow a lifetime of more than $20~\mathrm{C/cm^2}$ accumulated charge.
The pixelated read-out anode used is based on the Timepix4 ASIC ($65~\mathrm{nm}$ CMOS technology) designed in the framework of the Medipix4 collaboration.
This ASIC is an array of $512\times448$ pixels distributed on a $55~\mathrm{\mu m}$ square pitch, with a sensitive area of $\sim 7~\mathrm{cm}^2$.
It features $50$-$70~\mathrm{e^{-}}$ equivalent noise charge, a maximum rate of $2.5~\mathrm{Ghits/s}$, and allows to time-stamp the leading-edge time and to measure the Time-over-Threshold (\textit{ToT}) for each pixel.
The pixel-cluster position combined with its ToT information allows to reach $5$-$10~\mathrm{\mu m}$ position resolution.
This information can also be used to correct for the leading-edge time-walk achieving a timing resolution of the order of $10~\mathrm{ps}$.

The detector will be highly compact thanks to the encapsulated front-end electronics allowing local data processing and digitization.
An FPGA-based data acquisition board, placed far from the detector, will receive the detector hits using $16$ electro-optical links operated at $10.24~\mathrm{Gbps}$.
The data acquisition board will decode the information and store the relevant data in a server for offline analysis.

These performance will allow significant advances in particle physics, life sciences, quantum optics or other emerging fields where the detection of single photons with excellent timing and position resolutions are simultaneously required.

Speaker: Dr Nicolo Vladi Biesuz (Universita e INFN, Ferrara (IT))

Development of a single-photon imaging detector with pixelated anode and integrated digital readout(1).pdf

151 A Novel Ultra-High-Speed CMOS Image Sensor Implementation with Variable Spatial and Temporal Resolution using Temporal Pixel Multiplexing

Temporal Pixel Multiplexing (TPM) is a new imaging modality allowing one CMOS image sensor to do the job of both high-resolution still photography and high-speed video with equal ease. Based on the desired trade-off between the number of frames in a high-speed burst and the video resolution, the sensor splits the pixel array into multi-pixel sub-groups defined prior to image capture. The current TPM design provides a high degree of flexibility in setting the size of these sub-groups, e.g., 2x2, 3x3, etc., and evenly distributes the resulting pixel groups across the entire array. When acquiring a single image frame, all pixels are exposed with the same integration time using a global shutter operation. Data is then readout as in a standard CMOS image sensor. When high-speed video is to be acquired, each pixel in a sub-group is exposed with a different integration time. These times have the same length, but can be offset from each other, resulting in each pixel acquiring a different frame of the high-speed video. The sensor presented here can offset these times by as little as 100ns. Therefore, for example, a 9x9 sub-group can acquire 81 frames of 10Mfps video footage. The resulting output is a single high-resolution image that can be post-processed into a short movie, formed from an ultra-high-speed sequence of lower resolution frames, consisting of pixels which have been exposed at the same time and collected together. This demonstrates the key benefit of the TPM technique - the capability to retrieve both a high-resolution image and a high-speed image sequence from a single picture with no added readout noise.

We present the first silicon implementation of a CMOS sensor employing the TPM imaging technique. The presentation covers the TPM sensor architecture, performance and functionality test results, and application benefits of the TPM method.

Speaker: Deividas Krukauskas (Science and Technology Facilities Council)

TPM_presentation_PSD_pdf.pdf

152 Precise timing and recent advancements with segmented anode PICOSEC Micromegas prototypes (in-person)

Emerging challenges in current and future accelerator facilities appoint timing as an important variable to resolve extremely large event multiplicities on particle detection systems. The PICOSEC Micromegas detector has demonstrated the ability to time 150GeV muons with sub-25ps precision. Driven by detailed simulation studies and a phenomenological model, which describes stochastically the dynamics of the signal formation in the detector, new PICOSEC designs were developed that significantly improve the timing performance of the detector. As an example, PICOSEC prototypes with reduced drift gap size (∼ 119μm) reached a resolution of 45ps (in comparison to 76ps of the standard PICOSEC prototype) in timing single photons in laser beam tests.
Towards large area coverage detectors, the approach of a multi-pad PICOSEC prototype with a segmented anode has been selected and developed. Extensive tests in particle beams revealed that the multi-pad version of the PICOSEC achieve time resolution comparable with the single-pad detector, even when the MIP induced signal is shared among several neighbouring pads.
An overview of results, incorporating recent advancements on the PICOSEC instrumentation will be presented along with studies for new photocathode materials, resistive anode technologies as well as digitization electronics, for a scalable, radiation hard, resistive PICOSEC Micromegas detectors for very precise timing.

Speaker: Dr Ioannis Manthos (University of Birmingham (GB))

PSD12_Manthos.pdf

13:00 Packed Lunch for Coach

Afternoon and Evening Trip to Straford-upon-Avon Including Performance of Shakespeare's The Comedy of Errors from 6.30pm at The Royal Shakespeare Company

List of attractions in Stratford upon Avon

One suggestion for eating

Suggested activities in Stratford upon Avon

Visitor Information Centre

walksleaflet.pdf

Friday, 17 September

Poster Sesion 6 (Advances in Pixel Detectors and Integration Technologies)

Advances in Pixel Detectors and Integration Technologies

Conveners: Philip Patrick Allport (University of Birmingham (UK)), Laura Gonella (University of Birmingham (UK))

153 Design and prototype performance of Macro-Pixel Sub-Assemblies for the CMS Outer Tracker upgrade

The CMS silicon tracker will be replaced for the HL-LHC run of the experiment during LS3. The outer part of the new tracker is called Outer Tracker and consists of six barrel layers and endcap disks. Two types of modules have been designed, 2S modules (made up of two strip sensors) and PS modules (made of one strip, one macro-pixel sensor). The macro-pixel part of the PS module is called Macro-Pixel Sub-Assembly, or MaPSA. We will present the design of the MaPSA and show results from an extensive prototyping phase with multiple bump-bonding vendors. Plans for production will also be discussed.

Speaker: Jennet Elizabeth Dickinson (Fermi National Accelerator Lab. (US))

Dickinson_PSD12_MaPSA_vf.pdf

154 Future Upgrade for LHCb VELO

LHCb has recently submitted a physics case to upgrade the detector to be able to run at instantaneous luminosities of 2$\times 10^{34} cm^{-2}s^{-1}$, an order of magnitude above Upgrade I, and accumulate a sample of more than 300 fb$^{-1}$. At this intensity, the mean number of interactions per crossing would be 56, producing around 2500 charged particles within the LHCb acceptance. The LHCb physics programme relies on an efficient and precise vertex detector (VELO) to correctly identify the origin point of the b/c decays. To meet this challenge it is necessary to use temporal precision on each hit at the pixel detector region. To achieve this goal a new 4D hybrid pixel detector with enhanced rate and timing capabilities in the ASIC and sensor will be developed. Improvements in the mechanical design will be needed to allow periodic module replacement and lower detector material.

The early stages of R\&D and conceptual design of a 4D VELO will be presented, together with extensive simulation studies showing the prospects of the 4D-tracking approach on physics measurements, compared to typical 3D and timing plane alternatives.

Speaker: Jakob Haimberger (CERN)

Jakob Haimberger.pdf

155 Testbeam performance results of bent ALPIDE MAPS in view of the ALICE Inner Tracking System 3

The ALICE Inner Tracking System (ITS) has been recently upgraded to a full silicon detector consisting entirely of Monolithic Active Pixel Sensors (MAPS), arranged in seven concentric layers around the beam pipe. Further ahead, during the LHC Long Shutdown 3, ALICE intends to replace the three innermost layers of this new ITS with a novel vertex detector. To accomplish this, the proposed design features wafer-scale, ultra-thin, truly cylindrical MAPS. The new sensors will be thinned down to 20-40 $\mu$m, featuring unprecedented low material budget of below 0.05% X0 per layer and will be arranged concentrically around the beam pipe, as close as 18 mm from the interaction point.

Anticipating the first prototypes in the new 65 nm technology node, an active R&D programme is underway to test the response to bending of existing 50 $\mu$m-thick ALPIDE sensors. A number of such chips were successfully bent, even below the targeted innermost radius, without signs of mechanical damage, while retaining their full electrical functionality in laboratory tests. The curved detectors were subsequently tested during particle beam campaigns, where their particle detection performance was assessed.

In this contribution, testbeam highlights from the data analysis of bent ALPIDE sensors, will be presented. It was proved that the current ALPIDE 180 nm technology retains its properties after bending. The results show an inefficiency that is generally below $10^{-4}$, independent of the inclination and position of the impinging beam with respect to the sensor surface. This encouraging outcome proves that the use of curved MAPS is an exciting possibility for future silicon detector designs, as the sensor can not only survive the bending exercise, but its performance as a vertex detector is comparable to that in the flat state.

Speaker: Mr Bogdan Mihail Blidaru (ALICE Collaboration)

Bogdan Blidaru 2.pdf

156 CMOS pixel sensors optimized for large ionizing dynamic

Monolithic active pixel sensors (MAPS) are now well established as a technology for tracking charged particles, especially when low material budget is desirable. For such applications, the design of the sensor focus mainly on optimizing the spatial resolution. Small pixels with coarse charge measurement and digital outputs are well suited for this purpose.
Within the European Union’s STRONG project that focuses on experiments using hadrons, the TIIMM joint research activity intends to expand granular MAPS capacity to energy-loss (ΔE) measurement. The project targets to develop sensors for a wide input signal range. Covering energies from minimum ionization particles up to heavily ionization ions, such as carbon at few 100s MeV/u. The foreseen MAPS will combine tracking and identification.

The design challenge lies in the implementation of the front-end electronics in a small pixel (about 40 µm x 40 µm) that will be capable of operation with a wide dynamic range of the input signals (of the order of 1:105). .
TIIMM exploits recent advances in CMOS pixel sensors, where the sensitive layer is fully or partially depleted, allowing faster and more efficient charge collection.
in order to explore the tradeoff between fluctuations of the released charge and the minimization of multiple scattering.

The pixel architecture contains a charge sensitive amplifier with a Krummenacher feedback, a comparator and the digital logic performing the time-over-threshold measurements with 6-bit precision. First sensor prototype has been fabricated in the Tower-Jazz 180nm technology in 2020. The second corrected version is foreseen for a submission in Q3 2021. Both sensors feature different analogue front-end designs that affect the extent of the dynamic range (in excess of 105 e- equivalent input charge) and the fluctuation of the time-over-threshold output.
This contribution will detail the result of the analogue design optimization and initial tests of the first prototypes.

Speaker: WEIPING REN (IPHC)

poster#140-PSD12-CMOS pixel sensors optimized for large ionizing dynamic-Weiping REN.pdf

157 The Topmetal-CEE Prototype, a Direct Charge Sensor for the Beam Monitor of the CSR External-target Experiment

The Cooler-Storage-Ring External-target Experiment (CEE) which is being constructed since 2020 is a spectrometer to study the properties of nuclear matter at high baryon density region. An online beam monitor that is based on the time projection chamber detection principle is being developed for the CEE to accurately determinate the beam incidence position. The Topmetal-CEE sensors are used as the anode array collecting electrons in the beam monitor.

The Topmetal-CEE prototype has been designed in a standard CMOS 130 nm process and is being fabricated. The sensor has 180 channels with a pitch of 100 µm. In each channel, electrons are collected by a charge collection electrode which is a top-most metal exposed the surrounding media, amplified by a charge sensitive amplifier, and then feed into a discriminator. The output of the discriminator is split into two path. One records time-of-arrival (ToA). The other records time-over-threshold (ToT). ToA information is recorded in a 8-bit register counter at 40 MHz and can be refined by a time-to-amplitude convertor (TAC). TOT is also recorded by a TAC. In order to reduce the dead time, 180 channels are split into two separate parts and then the information in each part is read out by a data-driving priority readout scheme independently. Each channel has its own address encoded by an address encoder. The analog amplitude of each TAC is digitized by a 13-bit pipeline Analog-to-Digital Convertor (ADC). The output codes of the ADC are grouped with the corresponding counter and address, and then they are transferred off chip with a serial speed of 4.4 Gbps.

In the conference, we will present the detailed design and preliminary test results of the Topmetal-CEE prototype.

Speaker: Dr Chaosong Gao (Central China Normal University)

ID166-Topmetal-CEE prototype.pdf

158 Design and integration of CMOS tracker layers in digital tracking calorimeter for pCT application

Proton Computed Tomography (pCT) is an emerging imaging modality in particle therapy as it enables direct reconstruction of 3D map of relative stopping power (RSP) values of the target. A typical pCT detector records the direction and position of every single particle before and after crossing the target and residual energy after crossing the target. A typical pCT detector is thus made of extra-thin tracking detectors and an energy/range detector.
Bergen pCT collaboration is building a prototype Digital Tracking Calorimeter (DTC) consisting of 43 layers of pixelated silicon radiation detectors. The first two layers, called as tracker layers, are used for tracking the position of the protons. The next 41 layers, separated by absorber Al plates are used as calorimeter. Each layer is made up of 108 CMOS Monolithic Active Pixel Sensors (MAPS), covering an area of 27 cm × 16.6 cm. Each sensor has almost half-million pixels of the size of 29.24 x 26.88 µm².
The tracker layers of DTC and their integration steps will be discussed in this paper. The task is extremely challenging due to the contradictive demands of minimization of multiple scattering vs. thermo mechanical stability. These large area tracking layers must have the least low-Z material budget possible, should be mechanically stable and maintained at reasonable working temperature conditions for MAPS. The following steps are included in the paper: 1. Fabrication of carbon fiber sheets with thermal conductivity comparable to aluminum, as a support and heat-transfer material on which MAPS will be mounted, 2. Single-point TAB ultrasonic bonding method used to mount the MAPS on aluminium-polyimide flexible microcables, 3. Details of the design of the mechanical support structure the layers and 4. First results of combined water and air cooling of the prototype tracking layers.

Speaker: Dr Shruti Mehednale (on Behalf of Bergen pCT collaboration, University of Bergen, Bergen, Norway)

Shruti Mehendale.pdf

159 Performance Measurements from Cosmic Muon Data using the Outer Barrel of the New ALICE Inner Tracking System

The upgraded Inner Tracking System (ITS) of ALICE consists of 7 concentric layers of a custom monolithic active pixel sensor design known as ALPIDE. The ALPIDE-based detector design reduces the material budget to 0.35 $\%$ $X_0$ per layer for the innermost three layers (Inner Barrel), and to 1.0 $\%$ $X_0$ per layer for the outermost four layers (Outer Barrel), compared to 1.14 $\%$ $X_0$ per layer in the previous ITS. The readout rate has been improved to 100 kHz for Pb-Pb interactions, the radius of the first layer of the ITS reduced from 39 mm to 23 mm and the pixel pitch reduced to O(30 $\mu$m) $\times$ O(30 $\mu$m). These changes will improve the impact parameter resolution and tracking efficiency of heavy-flavour hadrons and dileptons at low transverse momenta, launching ALICE into the precision era of hot QCD physics.
The Outer Barrel was constructed at 10 sites around the world before being fully assembled into the intended barrel geometry and integrated into the readout electronics at CERN by the end of 2019. In the first half of 2020, the Outer Barrel underwent a series of verification tests to explore the performance of the finalised system. In the latter half of 2020, roughly 5 million cosmic muon events were measured by the Outer Barrel to further characterise the detector performance and provide a data set to be used for spatial alignment. This contribution will include a summary of the performance measurements made so far with the Outer Barrel, including a first measurement of the detector efficiency.

Speaker: James Philip Iddon (University of Liverpool (GB))

jpi_psd_v2.pdf

160 Operational Experience and Performance with the ATLAS Pixel detector at the Large Hadron Collider at CERN

The tracking performance of the ATLAS detector relies critically on its 4-layer
Pixel Detector
The key status and performance metrics of the ATLAS Pixel Detector are
summarised, and the operational experience and requirements to ensure
optimum data quality and data taking efficiency will be described, with special emphasis to radiation damage experience.
By the end of the proton-proton collision runs in 2018, the innermost layer IBL,
consisting of planar and 3D pixel sensors, had received an integrated fluence of approximately Φ = 1× 10**15 1 MeV neq/cm2.
The ATLAS collaboration is continually evaluating the impact of radiation on the Pixel Detector. A quantitative analysis of charge collection, dE/dX, occupancy reduction with integrated luminosity, under-depletion effects with IBL, effects of annealing will be presented and discussed, as well as the operational issues and mitigation techniques adopted during the LHC Run2 and the ones foreseen for Run3.

PSD12_Poster_v2.pdf

161 Characterisation of HV-MAPS ATLASPix3 and its applications for future lepton colliders

High voltage CMOS pixel sensors have been proposed in several future particle physics experiments for particle tracking. ATLASPix3 is the first full reticle size (2×2 cm^2) Monolithic Active Pixel high voltage CMOS sensor, developed in context of the ATLAS upgrade for High Luminosity Large Hadron Collider (HL-LHC). It is designed to meet the specifications of outer layers of the ATLAS inner tracker (ITk) pixel subsystem. ATLASPix3 has been implemented in a standard 180nm HVCMOS process, containing 132 x 372 pixels, each with an area of 150 x 50 µm². The readout electronics supports both triggered and triggerless readout with zero-suppression. The excellent position resolution, high readout rate (40 MHz), and high radiation tolerance make ATLASPix3 an ideal candidate for large-area tracking detector R&D of future collider experiments. It is under study for the Circular Electron Positron Collider (CEPC) silicon tracker. New versions tailored to different experiments are under development.

Results of electrical tests, sensor calibration and measurements with radioactive sources and lasers will be presented on individual chips and first multi-chip-modules. Multi-module readout architectures and large prototype demonstrator design concepts will be discussed.

Speaker: Bianca Raciti (Università degli Studi di Milano)

Bianca Raciti.pdf

162 A 14-Gbps VCSEL Driving ASIC in 55 nm for Particle Physics Experiments

Low power consumption, high bandwidth and radiation tolerant VCSEL driving ASICs have been prevailingly researched and used in particle physics experiments. This paper presents the design and the test results of a 14-Gbps VCSEL driving ASIC fabricated in 55 nm CMOS technology.
The whole ASIC includes four independent channels, and each channel has the fixed channel height of 250 μm to keep the whole ASIC as the array form fitting with a four channel VCSEL array. The 14-Gbps VCSEL driver is implemented as one of the four channels. The 14-Gbps VCSEL driver ASIC consists of an equalizer stage, a pre-driver stage and a novel output driver stage. The equalizer stage adopts the Continuous Time Linear Equalizer (CTLE) structure to compensate for the high frequency loss. To obtain the high bandwidth, a shared inductance-peaking technique is used in the pre-driver stage. The proposed the novel output driver stage raises the supply voltage and employ the stacked PMOS current source structure to increase the swing amplitude of the driving current to the VCSEL. Besides, two feedforward compensation capacitors are utilized to improve the bandwidth of output driver stage.
The whole ASIC features a size of 2 mm x 2 mm. The 14-Gbps VCSEL driver has a size of 2 mm x 0.25 mm. Widely-open 14-Gbps eye has been observed at the typical settings of 2 mA bias current and 5 mA modulation current in the post layout simulation. The chip has been taped out and the tests are planned to be conducted in this May. The driver ASIC will use chip on board (COB) measurement setup, and is wire bonded to an 850 nm VCSEL. The optical test, electrical test and total ionizing dose (TID) test will be performed. The test results will be reported in the meeting.

Speakers: Cong Zhao (Central China Normal University), Prof. Di Guo (Central China Normal University)

PSD12-Zhao-14G VCSEL Driver ASIC Poster.pdf

Applications in Security and Environmental Imaging; Advances in Pixel Detectors and Integration Technologies 2

Conveners: David Smith (Brunel University London), Ioannis Kopsalis (University of Birmingham (GB))

163 Applications in Security and Environmental Imaging

Speaker: Vincent SCHOEPFF (CEA)

SCHOEPFF-Imaging_for_security_environment.pdf

164 X-ray/Neutron Flat-Panel Detector using LCD Technology (in-person)

In this study, we present the results of our evaluation of a newly created flat panel detector. We have adapted the liquid crystal display technology to create an array of thin-film transistors and photodiodes, which can be used for flat-panel detector for radiation imaging. Our prototype flat-panel detector has a pixel size of 50 μm square and 252 x 256 pixels. By combining this panel with a scintillator, we implemented a flat panel detector for X-rays and neutrons. The scintillator was ZnS/LiF with a thickness of 0.4 mm. First, we evaluated the spatial resolution of the flat-panel detector using X-ray. The X-ray tube voltage was set to 30-160 kV and the tube current to 3 mA. The time for total area scanning were 227 ms, and we repeated 1000 times for averaging the images. The spatial resolution was measured up to 2.5 LP/mm. Secondly, we evaluated the flat-panel detector using neutron beam in Japan Proton Accelerator Research Complex (J-PARC) MLF BL-10. The neutron intensity at BL-10 was $4.8×10^7 n/s/cm^2$ with neutron energies below 0.4 eV at the sample position. The total-area scanning was repeated 1000 times and images were integrated as in the case of X-rays. As a result, the images were successfully obtained for the neutron beam as well. We evaluated the spatial resolution using a Gd resolution gauge. As a result, 0.2 mm pitch (2.5 LP/mm) strips could be discriminated, and the spatial resolution was comparable to that of the X-ray cases.

Speaker: Mr Mohammad Hamdan (The University of Tokyo)

165 Measurements of time and spatial resolution of AC-LGADs with different designs

AC-LGAD sensors are prime candidates for fast and precise measurement of charged particles in a variety of applications. In a fine-pitched pixel or strip AC-LGAD sensor, the signal generated by the passage of a particle is not localized in a limited volume in the sensor, but is shared among multiple electrodes. This signal sharing characteristic allows us to improve the spatial resolution of AC-LGAD sensors beyond the capabilities of common silicon trackers. Since the magnitude of the shared signal depends on the distance between the pixels or strips and the point of passage of the particle, signal sharing is strongly influenced by the geometry of the sensor. The electrode pitch and gap size as well as the shape can be fine tuned to maximize the space resolution, while keeping the detector granularity and the number of channels to be read out under control. Prototypes of AC-LGAD sensors produced at the Brookhaven National Laboratory covering a variety of possible geometries have been studied via Transient Current Technique using an Infrared laser, and the signal sharing, spatial resolution, and time resolution of the different topologies have been measured. These results have been compared with measurements performed in test-beams with 120 GeV protons at the Fermilab Test Beam Facility, or with beta particles generated in the decay of a $^{90}$Sr source. A time resolution of $\sim$30 ps can be achieved using AC-LGAD sensors with a thickness of 50 $\mu$m, compatible to that of standard DC-coupled LGADs, while presenting a far superior spatial resolution. This combination of high precision, fast timing capabilities, and low material budget makes AC-LGADs an ideal choice for a truly 4D detector.

Speaker: Gabriele D'Amen (Brookhaven National Laboratory (US))

PSD12_Measurements_of_time_and_spatial_resolution_of_AC_LGADs_with_different_designs (6).pdf

166 Characterization of irradiated RD53A pixel modules with passive CMOS sensors (in-person)

We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. The availability of multi-layer routing will provide the freedom to optimize the sensor geometry and the performance, with biasing structures in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test-structures and RD53A compatible pixel sensors was recently completed at LFoundry in 150nm CMOS process. This presentation will focus on the characterization of irradiated and non-irradiated pixel modules, composed by a CMOS passive sensor interconnected to a RD53A chip. The sensors are designed with a pixel cell of 25$\times$100 $\mu m^2$ in case of DC coupled devices and 50$\times$50 $\mu m^2$ for the AC coupled ones. Their performance in terms of charge collection, position resolution, and hit efficiency was studied with measurements performed in the laboratory and with beam tests. The RD53A modules with LFoundry silicon sensors were irradiated to fluences up to 1016 neq/cm2.

Speaker: Arash Jofrehei (Universitaet Zuerich (CH))

LFoundry PSD12.pdf

167 Allpix Squared - Silicon Detector Monte Carlo Simulations for Particle Physics and Beyond

Allpix Squared is a versatile, open-source simulation framework for silicon pixel detectors. Its goal is to ease the implementation of detailed simulations for both single sensors and more complex setups with multiple detectors. While originally created for silicon detectors in high-energy physics, it is capable of simulating a wide range of detector types for various application scenarios, e.g. through its interface to Geant4 to describe the interaction of particles with matter, and the different algorithms for charge transport and digitization. The simulation chain is arranged with the help of intuitive configuration files and an extensible system of modules, which implement the individual simulation steps. Detailed electric field maps imported from TCAD simulations can be used to precisely model the drift behavior of the charge carriers, bringing a new level of realsim to the Monte Carlo simulation of particle detectors.

Recently, Allpix Squared has seen major improvements to its core framework to take full advantage of multi- and many-core processor architectures for simulating events fully parallel. Furthermore, new physics models such as charge carrier recombination have been introduced, further extending the application range. This contribution provides an overview of the framework and its components, highlighting the versatility and recent developments.

Speaker: Simon Spannagel (Deutsches Elektronen-Synchrotron (DE))

2021-09-17-PSD12-APSQ.pdf

10:30 Coffee/Tea

Poster Session 7 (Detectors for High Radiation and Extreme Environments)

Detectors for High Radiation and Extreme Environments

Conveners: Carl Wheldon (University of Birmingham), Tony Price (University of Birmingham (GB))

168 Investigation of Mixed Bulk Radiation Damage Effects in p-MCz Thin Silicon Microstrip Detector for Phase 2 Upgrade of the new CMS Tracker Detector at HL-LHC

A lot of R & D work is carried out in the CERN RD50 Collaboration to find out the best material for the Si detectors that can be used in the harsh radiation environment of HL-LHC, n and p-MCz Si was identified as one of the prime candidates as a material for n in p strip detector that can be chosen for the phase 2 upgrade plan of the new Compact Muon Solenoid tracker detector in 2026.
For the very first time, an advanced four level deep-trap mixed irradiation model for p-MCz Si is proposed by the comparison of experimental data on the full depletion voltage and leakage current to the Shockley Read Hall recombination (SRH) statistics results on the mixed irradiated p-MCz Si PAD detector.
In this work, we have determined the effective introduction rate ηeff of shallower donor deep trap E30 K using SRH theory calculations for exp. Neff and that can be shown the behaviour of space charges and electric field distribution in the p-MCz Si strip detector and compared its value with the ηeff of shallower donor deep trap E30 K in the n-MCz Si microstrip detector.
Prediction uncertainty in the p-MCz Si radiation damage mixed irradiation model considered in the full depletion voltage and leakage current. A very good agreement is observed in the experimental and SRH results. This p-MCz Si radiation damage model is used to extrapolate the value of the full depletion voltage at different mixed (proton + neutron) higher irradiation fluences for the thin p-MCz Si microstrip detector.

Speaker: Ms Shilpa Patyal (Chandigarh University)

PSD12 UK123 (1).pdf

169 Comparison study of heavily irradiated dielectrics for AC-coupled pixel detectors

The motivation of this study is the development of next generation capacitively coupled (AC-coupled) pixel sensors with coupling insulators having good dielectric strength and radiation hardness simultaneously. The AC-coupling insulator thin films were aluminum oxide (Al2O3) and hafnium oxide (HfO2) grown by Atomic Layer Deposition (ALD) method. The Al2O3 thin films were patterned for finely segmented structures by traditional wet etching, whilst HfO2 was patterned by Chemical Mechanical Polishing (CMP) into structures defined by Reactive Ion Etching (RIE).
The results focus on a comparison study based on the dielectric material used in MOS, MOSFET and AC-pixel sensors processed on high resistivity p-type Magnetic Czochralski silicon (MCz-Si) substrates. These test structures were irradiated with 10 MeV protons up to a fluence of 5e15 p/cm2. Capacitance-voltage measurements of MOS and MOSFET test structures indicate negative oxide charge accumulation induced by proton irradiation. These studies are coherent to numerical simulations, as well as gamma irradiated MOSFET samples. Furthermore, current-voltage (I-V) measurements indicate very good dielectric strength performance in both the materials, even after proton irradiation. Electrical characterisation to study the impact of different dielectric-silicon interfaces on the functionality of the AC-pixel sensors was further investigated by edge-TCT (Transient Current Technique) method. The negative oxide charge during the irradiation is an essential prerequisite of radiation hardness resiliency of n+/p−/p+(n on p) particle detectors widely intended to be used in future high-luminosity experiments.

Speaker: Shudhashil Bharthuar (Helsinki Institute of Physics (FI))

PSD12_POSTER_Final__S__Bharthuar_.pdf

170 TCAD Simulation of Radiation Hard n-MCz and n-Fz Si Microstrip Detector for the HL-LHC

Radiation damage of the silicon strip detectors in the HL-LHC experiments pretenses a major task for its reliable long –term operation of the experiment. Radiation hard Si detectors have used in the new CMS tracker detector at HL-LHC in 2026. It has been observed that n-MCz and n-Fz Si as a material can be used for the Si microstrip detector. The strip detector design for this material should be simulated using TCAD simulation and optimized to get the high CCE. In order to understand the charge collection behavior of the n-MCz/n-Fz Si detector, we have compared the radiation damage effects in the mixed irradiated n-MCz Si and neutron irradiated n-Fz Si microstrip detector equipped with metal overhang and multiple guard rings.
In this paper, we have shown an optimal design of the radiation hard n-MCz Si/n-Fz Si strip detector design for the HL-LHC experiment in order to get high CCE.

Speaker: Mrs Balwinder Kaur (Chandigarh University)

Balwinder_PSD12 UK.pdf

171 A table-top Two Photon Absorption – TCT system: measurements of irradiated and non-irradiated silicon sensors

The Transient Current Technique (TCT) is widely used in the field of silicon particle
detector development. So far, mainly Single Photon Absorption – Transient Current
Technique (SPA-TCT) was performed, using laser wavelengths with a photon energy
larger than or similar to the silicon band-gap. Recently, measurements employing two
photon absorption for the testing of the silicon bulk properties were carried out for
the first time. Excess charge carriers are generated only in a small volume (approx. 1
um x 1um x 20 um) around the focal point of the laser beam, so that resolution in all
three spatial directions is achieved. Furthermore, compared to what is customary in
SPA-TCT, the resolution perpendicular to the incident laser beam was increased one
order of magnitude. Following the initial success of the method, a compact Two
Photon Absorption – Transient Current Technique (TPA-TCT) setup has been
developed and first measurements were performed. The current status of the setup
and the results obtained on non-irradiated silicon strip and LGAD sensors as well as
irradiated LGAD sensors will be covered in this talk.

Speaker: Sebastian Pape (Technische Universitaet Dortmund (DE))

Sebastian Pape.pdf

172 Double injection studies on the RD53B-ATLAS chip

Operation at the High Luminosity LHC (HL-LHC) requires the pixel detectors of ATLAS and CMS to separate collisions occurring with an extremely high pile-up. Fast detectors with a small pixel size are therefore needed such that thousands of charged particles per event can be reconstructed with high fidelity and excellent vertexing resolution.

The RD53 collaboration has been working on the design of a dedicated readout chip to meet these goals, the RD53 chip. This chip will be part of a hybrid device composed of one or more readout chips bump-bonded to a silicon sensor. In this study, we have tested one of the pre-production versions, the RD53B-ATLAS chip.

This talk present charge injection tests performed on the RD53B-ATLAS chip, specifically looking at its response when a pixel is exposed to injections happening close in time. This was achieved by using a novel feature introduced in the RD53 chip. Here, one can perform two injections in rapid succession by utilizing the specialized charge injection circuit attached to each pixel input. In this way, we were able to inject two consecutive charge injections with varying magnitude with a time gap as small as 5 bunch crossings (125 ns).

The purpose is to study the behaviour of the analog front-end, focusing on events where charge deposition of a particle can happen so rapidly that a preceding hit affects the readout of a subsequent hit. These events are more likely to occur in a high-pile up environment.

Results show that the measured charge of an injection is changed by a preceding injection and that this effect scales with the injected magnitude. This is seen by the threshold and the precision Time over threshold values (pToT) measured on the subsequent injection. The results can be explained by the discharge rate of the primary injection.

Speaker: Simon Kristian Huiberts (University of Bergen (NO))

Double injection studies on the RD53B-ATLAS chip (09.16.2021).pdf

173 Simulation of Pixel Silicon detectors for experiment at high luminosity colliders.

Silicon detectors are expected to suffer unprecedented radiation damage in future high-luminosity collider detectors. Device modelling is required for detailed understanding of the performance of silicon detectors over the lifetime of the detector and to set design rules to mitigate the detrimental effect provided by radiation damage.

In the present work, results of a comprehensive simulation of the silicon pixel detector, based on TCAD-Synopsys are presented. The simulation work focuses on the Pixel detector with a 25 micron pitch, the smallest pitch used for the main vertex detectors by the HL-LHC experiments.
A detailed simulation of the device has been implemented in order to study the operating conditions of the Pixel detector. This is done through the simulation of the leakage current and the total depletion voltage as well as to study the detection performance through the simulation of the charge collection efficiency and the point spatial resolution. Furthermore, the comparison of the results is carried out with measurement and simulation based on data published by TCAD-Silvaco.

Speaker: Ms S. Parolia (Universita & INFN Pisa (IT))

174 Characterization of passive CMOS strip detectors

Silicon detectors are currently filling the trackers of largest particle accelerators and colliders. Their radiation hardness, spatial resolution and availability in large volume foundries make silicon the best candidate for tracking detectors. Current experiments such as ATLAS in the LHC and future experiments foresee to populate the innermost tracking layers with silicon detectors. But not so many foundries are capable of fabricating large area silicon detectors with a production line, therefore CMOS foundries are excellent candidates to be explored.

Here we study the performance of passive strip detectors fabricated in a CMOS foundry with a 150 nm technology process and 150 µm thick wafer. The strips have two different lengths with three or five stitching points, produced using two different reticles. It will be presented the electrical characterization, studies with a radioactive source and testbeam results for the passive CMOS strip sensors before and after irradiation. We will demonstrate that stitching strips do not have any negative effect on their performance.

Speaker: Marta Baselga (Deutsches Elektronen-Synchrotron (DE))

passive_CMOS_mbaselga.pdf

175 A Novel Front-End Amplifier for Gain-less Charge Readout in High-Pressure Gas TPC

The search for Neutrinoless Double-Beta Decay (0νββ) at tonne-scale and beyond requires techniques that are capable of observing a sharp peak at Qββ in the total beta energy spectrum. A direct charge sensor, Topmetal-S, with only one charge collection electrode on a single sensor and with the intention to tile many such sensors on a large plane, is being developed for 0νββ experiments in a high-pressure gaseous Time Projection Chamber (TPC) without gas-electron avalanche. This scheme eliminates the conventional avalanche fluctuations but demands exceedingly low internal noise on the front-end amplifier to achieve sufficient energy resolution by charge measurement alone.

Given a power consumption and circuitry, the electronic noise of the front-end amplifier is proportional to the input capacitance primarily contributed by the Charge Collection Electrode (CCE), the input metal routing and the input transistor. An exposed hexagon metal with a diameter of 1mm is proposed as the CCE on the topmost layer. Its capacitance with respect to the ground is around 4pF. If the input capacitance is reduced, the electronic noise could be significantly decreased.

A novel front-end amplifier composed of a source-drain follower and a common-source amplifier is proposed. The potential on both the source and drain node of the input transistor follows its gate. Hence the effective input capacitance contributed by the input transistor is significantly reduced. If both the CCE and the input metal routing are also shielded and the shield is coupled to the source or drain node, the input capacitance can be greatly reduced. A test chip with the novel front-end amplifier and the CEE has been designed in a standard CMOS 130nm process and is being manufactured. The simulation shows that the equivalent noise charge is less than 30e-.

In the conference, we will present the detailed design and preliminary test results.

Speaker: Dr Chaosong Gao (Central China Normal University)

poster-A Novel Front-End Amplifier for Gain-less Charge Readout in High-pressure Gas TPC9.11 - PSD12(1).pdf

176 Instrumentation Challenges of the strong-field QED experiment LUXE at the European XFEL

The LUXE experiment aims at studying high-field QED in electron-laser and photon-laser interactions, with the 16.5 GeV electron beam of the European XFEL and a laser beam with power of up to 350 TW. The experiment will measure the spectra of electrons and photons in non-linear Compton scattering where production rates in excess of 109 are expected per 1 Hz bunch crossing. At the same time positrons from pair creation in either the two-step trident process or the Breit-Wheeler process will be measured, where the expected rates range from 10-3 to 103 per bunch crossing, depending on the laser power and focus. These measurements have to be performed in the presence of low-energy high radiation-background. To meet these challenges, for high-rate electron and photon fluxes, the experiment will use Cherenkov radiation detectors, scintillator screens, sapphire sensors as well as lead-glass monitors for backscattering off the beam-dump. A four-layer silicon-pixel tracker and a compact electromagnetic tungsten calorimeter with GaAs sensors will be used to measure the positron spectra. The layout of the experiment and the expected performance under the harsh radiation conditions will be presented.

Speaker: Kyle Fleck (Queen's University Belfast)

Kyle Fleck.pdf

177 Development, construction and qualification tests of the Mu2e electromagnetic calorimeter mechanical structures

The Mu2e experiment at Fermilab will search for the CLFV neutrino-less coherent conversion of a muon into an electron in the field of an aluminum nucleus. The observation of this process would be the evidence of physics beyond the Standard Model. Mu2e comprises a straw-tracker, an electromagnetic calorimeter and an external veto for cosmic rays. The calorimeter provides electron identification, a fast trigger and aids track reconstruction. It is a state-of-the-art crystal calorimeter and employs 1340 pure CsI crystals readout by UV-extended SiPM and fast electronics. The design consists of two identical annular disks positioned at the relative distance of 70 cm downstream the target.
The hostile Mu2e conditions (total ionizing dose of 12 krad and a neutron fluence of 5x1010 n/cm2 @ 1 MeVeq (Si)/y, 1 T magnetic field and vacuum level of 10^-4 Torr) posed tight constraints on the mechanical structures and materials choice. The support structure of the two crystal matrices employs two aluminum hollow rings and parts made of open-cell vacuum-compatible carbon fiber. SiPMs and front-end electronics for each crystal are assembled in one mechanical unit inserted in a machined copper holder. The units are supported by a plate made of vacuum-compatible material. The plate integrates the cooling system made of a network of copper lines flowing a low temperature fluid and placed in thermal contact with the copper holders. The DAQ is hosted in aluminum crates positioned on the lateral surface of the disks. The crates also integrate the DAQ electronics cooling system. We review the constraints on the calorimeter structures design, the development of all the structural components, including the simulations that have determined the materials and technological choices and the specifications of the cooling station, components production and quality assurance tests, the procedures for detector assembly, transportation and installation in the experimental area.

Speaker: Daniele Pasciuto

poster.pdf

Detectors for High Radiation and Extreme Environments

Conveners: Ioannis Kopsalis (University of Birmingham (GB)), Philip Patrick Allport (University of Birmingham (UK))

178 Detectors for High Radiation and Extreme Environments

Speaker: Gregor Kramberger (Jozef Stefan Institute (SI))

Kramberger-ExtremeFluences-PSD12.pdf

179 Timing detectors with scCVD diamond crystals: the CMS Precision Proton Spectrometer timing system.

The intrinsic characteristics of CVD diamonds, their superior radiation hardness and the thermal properties make of them an ideal candidate for a timing and/or position detector operated in harsh condition, where high irradiation is foreseen or where appropriate cooling of the sensor surface is undesirable or impractical. Moreover, their fast response to the passing particle make them suitable for high rate environment. Different custom geometries can be implemented for the electrodes through metallization or graphitization in both planar and 3D architectures. The CMS Proton Precision Spectrometer (PPS) consists of 3D silicon tracking stations, measuring both the position and direction of protons scattered in the very forward region, as well as timing detectors based on planar single crystal CVD diamond, measuring the proton time-of-flight with high precision. The detectors are hosted in special movable vacuum chambers, the Roman Pot, which are placed in the primary vacuum of the LHC beam pipe. Detectors have to operate in a vacuum at few mm from the primary LHC beam and must be able to sustain and highly non-uniform irradiation, with local peak above $10^{16}neq/cm^2$. In this presentation, after an introduction to the diamond technology, we will describe the PPS timing system. The sensor architecture, with two diamond sensors read out in parallel by the same electronic channel, the dedicated amplification chain and the strategies used to digitize the signals will be described. Latest results on the timing detector performance during LHC Run 2, in terms of efficiency and time precision, will be reported. Timing detectors used in Run 2 have been dismounted and tested for efficiency and timing performance. The final results, here reported, are important to understand the effect of the radiation on such devices. The ongoing upgrades and consolidation activities for the upcoming LHC Run 3 will be finally discussed.

Speaker: Edoardo Bossini (Universita & INFN Pisa (IT))

PSD12_Bossini.pdf

180 First results from thin silicon sensors irradiated to extreme fluence

In this contribution, we present a new development of radiation-resistant silicon sensors produced by the Fondazione Bruno Kessler (FBK, Italy). The design of the sensors exploits the recently observed saturation of radiation damage effects on silicon, together with the usage of thin substrates, intrinsically less affected by radiation. To cope with the small signal coming from thin sensors, the internal multiplication of the charge carriers will be used. At FBK, Low-Gain Avalanche Diodes (LGADs) have been produced on 25 and 35 $\mu$m thick p-type epitaxial substrates: when new, the signal multiplication will occur due to the gain layer typical of the LGAD design; after irradiation, the loss of gain resulting by the deactivation of the gain layer atoms will be compensated by the increase of the operating bias. The goal is to prove that the new sensors can efficiently operate up to fluences of 1E17 1MeV neutron equivalent/cm$^2$.

Speaker: Valentina Sola (Universita e INFN Torino (IT))

vs_eXFlu_PSD12.pdf

181 Compact LumiCal prototype tests for future e+e- collider

The FCAL collaboration is preparing large-scale prototypes of special calorimeters to be used in the very forward region at a future electron-positron collider for a precise and fast luminosity measurement and beam-tuning. LumiCal is designed as silicon-tungsten sandwich calorimeter with very thin sensor planes to keep the Moliere radius small, facilitating such the measurement of electron showers in the presence of background. Dedicated FE electronics has been developed to match the timing and dynamic range requirements.
A partially instrumented prototype was investigated in a 1 to 5 GeV electron beam at the DESY II synchrotron. In the recent beam tests, a multi-plane compact prototype equipped with thin detector planes fully assembled with readout electronics were installed in 1 mm gaps between tungsten plates of one radiation length thickness. High statistics data were used to perform sensor alignment, and to measure the longitudinal and transversal shower development in the sandwich. In addition, Geant4 MC simulations were done and compared to the data.

Speaker: Dr Veta Ghenescu (Institute of Space Science)

VG_talk_psd12_last.pdf

182 A comprehensive overview of the extensive studies on the irreversible breakdown of the LGAD’s behavior at ELI Beamlines in fs-laser beam-tests with the sensors irradiated at critical LHC-HL fluences

The HL-LHC presents unprecedented challenges and timing information that is expected to play a key role to mitigate the impact of pile-up in both CMS and ATLAS. Broadly speaking, a timing detector is considered to improve the assignment of tracks to vertices in the forward region, which impacts electron ID, jet reconstruction, missing transverse energy and b-tagging. For future accelerators, LGADs as timing sensors, are also an interesting option in lepton accelerators, where timing can improve performance in particular for PID. However, after irradiation timing performance degrades due to loss of gain. To recover, it is important to increase the HV bias. Some devices show am irreversible breakdown while operating in these conditions and this remains a serious concern for both, yield and the LGAD’s operation stability. Many systematic studies and dedicated beam-tests at DESY, FNAL and CERN have been performed. Here we present an overview of the fatality tests performed in few dedicated test-campaigns on LGADs at ELI beamlines where we developed a powerful fs-laser based TCT-SPA/TPA experimental infrastructure. Both SPA and TPA were applied. Stable, unstable, critical, and irreversible breakdown phases were distinguished and safety HV bias thresholds set. The images of damaged sensors and HV threshold points for safety LGAD operation will be discussed as well as future strategies pointed out.

Speaker: Gordana Lastovicka Medin (University of Montenegro (ME))

PSD12_SEE_LGAD_GordanaMedin.pdf

PSD12_SEE_LGAD_GordanaMedin.pptx

183 Poster Prize (with thanks to Nature Review Physics), Announcement of PSD13 Location, Optional Packed Lunch and Farewells

Speakers: Tony Price (University of Birmingham (GB)), Prof. Daniela Bortoletto (University of Oxford (GB)), Philip Patrick Allport (University of Birmingham (UK))

Farewells.pptx

PSD12 Poster Awards.pdf

PSD12 Poster Awards.pptx

PSD12 Proceedings.pdf

PSD12 Proceedings.pptx

PSDinOxford.pptx