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12-16 September 2022
This conference is dedicated to the memory of Jacques Séguinot, one of the inventors of the Ring Imaging Cherenkov technique, who passed away on 12 October 2020. More information is provided here.
The Workshop will present the “state of the art” and the future developments in Cherenkov light imaging techniques for applications in High Energy Physics, Nuclear Physics and Astroparticle Physics. The conference is organized in plenary sessions of invited and contributed talks, and poster presentations. The list of topics includes:
• Cherenkov light imaging in particle and nuclear physics experiments;
• Cherenkov light imaging in neutrino and astroparticle physics experiments;
• Pattern recognition and data analysis;
• R&D for future experiments;
• Photon detection techniques for Cherenkov imaging counters;
• Technological aspects and applications of Cherenkov light detectors.
The preliminary programme consists of nine half-day scientific sessions, together with a social programme, including an excursion and a banquet. Participants are encouraged to arrive on Sunday evening on the 11th of September in time for a stroll through the centre of Edinburgh up to the historic castle. The conference will end on Friday 16th of September afternoon.
The RICH2022 workshop is expected to take place in-person, in accordance with the UK guidelines. The status of the pandemic will be monitored and updated if required.
For any further details, please contact the organizers.
Organised by:
Sponsors:
35'+5'
The NA62 experiment is designed to measure the very rare kaon decay K+ -> pi+ nu nubar at the CERN SPS with 10% statistical precision. One of the challenging aspects of the experiment is the suppression of the K+ -> mu+ nu_mu decay whose branching ratio is 10 orders of magnitude higher than the one of the K+ -> pi+ nu nubar decay. Kinematics cuts and the use of the very different stopping power of muons and charged pions in calorimeters are used to reject the K+ -> mu+ nu_mu background. However, a Ring Imaging Cherenkov (RICH) detector with a very long focal length (17 m) is needed in NA62 to further suppress muon contamination by a factor 100 in a sample of charged pions with momentum between 15 and 45 GeV/c while keeping a reasonably high efficiency for the pion selection. With a total time resolution of 70 ps this RICH detector is also used to measure the arrival time of the pion and provide the experiment trigger. The talk will describe the technical aspects and the operation characteristics of the RICH detector with an eye to possible future upgrades and will present, for the first time, the basic performance (time resolution, ring radius resolution, ring centre resolution, single hit resolution and mean number of hits) measured on data collected in 2021/2022 using electron tracks.
The CLAS12 deep-inelastic scattering experiment at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab conjugates luminosity and wide acceptance to study the 3D nucleon structure in the yet poorly explored valence region, and to perform precision measurements in hadron spectroscopy.
A large area ring-imaging Cherenkov detector has been designed to achieve the required hadron identification in the momentum range from 3 GeV/c to 8 GeV/c, with the kaon rate about one order of magnitude lower than the rate of pions and protons. The adopted solution comprises aerogel radiator and composite mirrors in a novel hybrid optics design, where either direct or reflected light could be
imaged in a high-packed and high-segmented photon detector.
Among the innovative components are: aerogel of n=1.05 and cutting-edge transparency; modular spherical mirror in a light composite material; planar glass-skin mirrors, unprecedented in nuclear physics experiments; and large-area multi-anode photomultipliers readout by a modular electronics.
The first RICH module was assembled during the second half of 2017 and successfully installed at the beginning of January 2018, in time for the start of the experiment. A second RICH module is in the final stage of assembling with the goal to be ready, despite the delays caused by the pandemic crisis, for the operation with polarized targets in summer 2022.
In the presentation, the detector performance will be discussed with emphasis on the operation and stability during the data-taking, calibration and alignment procedures, reconstruction and pattern recognition algorithms, and particle identification.
During the second LHC long shutdown, the LHCb experiment underwent a major upgrade in order to be able to operate at the instantaneous luminosity of 2 × 10−33 cm−2 s−1, reading data at a rate of 40 MHz, with a fully software-based trigger.
The RICH system of LHCb has been completely refurbished installing new photon detectors (Multi-anode Photomultiplier Tubes) equipped with a custom developed read-out chain. In order to reduce the unprecedented peak occupancy, the full optics and mechanics of the RICH1 detector has been re-designed to distribute the Cherenkov photons over a larger surface of the photon detectors planes.
The overview of the RICH upgrade programme is described including the design, installation and commissioning phase. The validation of the newly installed detectors, together with early performance studies is presented.
The High Momentum Particle IDentification (HMPID) detector successfully participated to the LHC Run 1 (2009-2013) and Run 2 (2015-2018) data taking periods, providing the expected contribution to the ALICE physics program. The detector showed so far very stable PID performance, ensured by the stability of its different condition parameters, i.e., MWPCs gain, photocathode quantum efficiency, and liquid radiator transparency. Approaching the LHC Run 3 period, the HMPID is fully integrated in the new ALICE computing framework (O2) and Trigger environment. The HMPID status and the activities undertaken to get the detector compliant with the new experiment requirements will be presented. The detector performance obtained with the first available data from LHC Run 3 period, will be discussed and the perspective of the physics contribution in the ALICE program will be shortly mentioned.
The ring imaging Cherenkov detector of the High Acceptance Dielectron Spectrometer (HADES) at GSI Darmstadt, Germany, has been upgraded with a new photon detection device based on 428 multianode photo electron multipliers (Hamamatsu H12700) partly coated with \textit{p}-Terphenyl as a wavelength shifter.
It is the key component for efficient identification of electrons and positrons emitted from hot and dense fireballs produced in heavy ion collisions.
Operated with a gaseous $\textrm{C}_4\textrm{H}_{10}$ (isobutane) radiator the RICH is essentially hadron blind for particle momenta up to approximately $2\,$GeV/c.
In total, 27392 MAPMT channels are read out by the FPGA based DIRICH readout electronic scheme which is also going to be incorporated in the future CBM-RICH and PANDA-DIRC detectors.
The DIRICH readout allows to measure leading and trailing edges for each pixel pulse and hence time over threshold and hit arrival time down to sub-nanosecond precision.
Within the FAIR-0 research program, a Ag+Ag run at $E = 1.58\textrm{A}\,$GeV incident energy marked the first beam time use of the upgraded RICH.
The detector could be operated at sustained triggered event rates of 16 to 18\,kHz with high electron purities while keeping large efficiencies for a recorded data sample of $\sim 15\times10^9$ events.
We present key features of the upgrade and report performance results of the RICH for this whole measurement campaign.
* Work supported by GSI, GSI Helmholtzzentrum für Schwerionenforschung, Campus Gießen, BMBF contract No. 05P15RGFCA, 05P19RGFCA, 05P21RGFC1, 05P15PXFCA, 05P19PXFCA, 05P21PXFC1 and Hessen für FAIR (HFHF)
The Belle II experiment at the SuperKEKB asymmetric-energy $e^{+}e^{-}$ collider is a B factory experiment to study rare decays with high precision such as $B\to\rho(\to\pi\pi)\gamma$ and $B\to K^{*}(\to K\pi)\gamma$. In order to study these processes, particle identification, especially the separation of charged kaons and pions is very important. In the Belle II detector, a proximity focusing Aerogel Ring Imaging CHerenkov counter (ARICH) is implemented to separate kaons from pions with momenta up to 4 GeV/$c$. The ARICH detector consists of a silica aerogel radiator and Hybrid Avalanche Photo Detector (HAPD) as the photon detector. Using the emission angle of the Cherenkov photon, the separation of the charged kaons from pions is performed.
The performance of the particle identification is studied using the collision data. The good separation between charged kaons and pions is observed, close to our expectations. We report the performance of the particle identification in the ARICH detector using the data.
The Belle II experiment started the physics run with full detectors in 2019 and accumulated more than 300 fb$^{-1}$of collision data. The ARICH detector has been operated stably and the performance of the HAPDs is consistent with our expectations. The concern is the deterioration of HAPDs due to silicon bulk damage by neutron radiations. The increase of the leakage current is observed due to the radiation, but the fluency of the neutrons is below the tolerable level. Currently, 94% of channels are operational and good performance is provided. The single event upset in the FPGAs due to the radiation is also considered. We implemented the scrubber of correcting radiation-induced errors in the firmware. Thanks to this implementation, the readout firmware has been running stably. In this presentation, we report the operation of ARICH including the fraction of dead channels and stability of HAPDs.
The GlueX experiment is located in experimental Hall D at Jefferson Lab (JLab) and provides a unique capability to search for hybrid mesons in high-energy photoproduction, utilizing a ~9 GeV linearly polarized photon beam. Phase II of the GlueX experiment began in 2020 with the installation of a Detector of Internally Reflected Cherenkov light (DIRC), utilizing components from the decommissioned BaBar DIRC. This upgrade will enhance the particle identification capability of GlueX by providing clean π/K separation up to 3.7 GeV/c momentum in the forward region (θ<11 deg), which will allow the study of kaon final states with significantly higher efficiency and purity. In this contribution we will discuss the status and performance of the GlueX DIRC from this initial dataset.
The PANDA experiment at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR), Darmstadt, Germany, will address fundamental questions of hadron physics using $\bar{p}p$ annihilations. Excellent Particle Identification (PID) over a large range of solid angles and particle momenta will be essential to meet the objectives of the rich physics program. Charged PID in the target region will be provided by a Barrel DIRC (Detection of Internally Reflected Cherenkov light) counter.
The Barrel DIRC, covering the polar angle range of 22-140 degrees, will provide a $\pi$/K separation power of at least 3 standard deviations (s.d.) for charged particle momenta up to 3.5 GeV/c. The design of the Barrel DIRC features narrow radiator bars made from synthetic fused silica, an innovative multi-layer spherical lens focusing system, a prism-shaped synthetic fused silica expansion volume, and an array of lifetime-enhanced Microchannel Plate PMTs (MCP-PMTs) to detect the hit location and arrival time of the Cherenkov photons. Detailed Monte-Carlo simulations were performed, and reconstruction methods were developed to study the performance of the system. All critical aspects of the design and the performance were validated with system prototypes in a mixed hadron beam at CERN. In 2020 the PANDA Barrel DIRC project advanced from the design stage to component fabrication. The series production of the fused silica bars was completed in 2021 and the first MCP-PMTs were delivered in 2022.
We will discuss the validation of the technical design using prototypes and present results from the quality assurance measurements for the bars and MCP-PMTs.
The IceCube Neutrino Observatory detects GeV-to-PeV+ neutrinos via the Cherenkov light produced by secondary charged particles from neutrino interactions with the South Pole ice. Relying on over 5000 spherical Digital Optical Modules (DOM), each deployed with a single downward-facing photo- multiplier tube (PMT) and arrayed across 86 strings over a cubic-kilometer, IceCube has measured the astrophysical neutrino flux while searching for their origins, as well as constrained neutrino oscillation parameters and cross sections. These were made possible by an in-depth characterization of the glacial ice, which has been refined over time, and novel approaches in reconstructions that utilize fast approximations of Cherenkov yield expectations.
After over a decade of nearly continuous IceCube operation, the next generation of neutrino telescopes at the South Pole are taking shape. The IceCube Upgrade will add seven additional strings in a dense infill configuration. Multi-PMT OMs will be attached to each string, along with improved calibration devices and new sensor prototypes. Its denser OM and string spacing will extend sensitivity to lower neutrino energies and further constrain neutrino oscillation parameters. The calibration goals of the Upgrade will help guide the design and construction of IceCube Gen2, which will increase the effective volume of IceCube by nearly an order of magnitude to probe astrophysical neutrinos at the energies we’ve yet to reach.
The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector with the primary physics goal of the neutrino mass hierarchy determination. The detector will be built in a laboratory at 700-m underground. . A Water Cherenkov veto system will be built for cosmic muon detection and background reduction. Outside the central detector, the pool is filled with 34 kton ultrapure water. The water Cherenkov light produced by cosmic muons are detected by 2400 MCP-PMT's. The inner surface of the water veto is covered with Tyvek reflector to increase the light collection efficiency. A water system is used for water purification and circulation to keep a high water quality for optimal detector performance. A set of radon removal equipment will be integrated with the water system to reduce the radon-induced background in the central detector. Based on prototype studies, the radon concentration in water in water could be reduced to 10mBq/m^3. The cosmic muon detection efficiency of the water Cherenkov detector is >99%. With this veto system, the cosmic muon-induced fast neutron background can also be reduced to ~0.1/day level.
The Large-Sized Telescopes (LST) are being deploying four imaging atmospheric Cherenkov telescopes in the Northern site of the future Cherenkov Telescope Array (CTA). The first prototype, LST-1, has been inaugurated at La Palma (Spain) in 2018 and is being commissioned since then while the three others will be built during three coming years. Thanks to their large dish of 23 m diameter, they can collect on the ground the light from the faintest extensive
atmospheric showers and achieve observation of gamma rays
with energies down to 20 GeV.
The status of the project will be presented with emphasis put on the key results from the commissioning phase, mostly focusing on the optics and Cherenkov camera performance. The first science results obtained with LST-1, such as observations of standard sources like the Crab Nebula and Crab pulsar, RS Ophiuchi and BL Lac will be shown demonstrating the high performance level reached in monoscopic operations. Eventually, the status of the production of the LST-2 to 4 will be given.
The ASTRI Mini-Array is an INAF project to build and operate a facility to study astronomical sources emitting very high energy in the TeV spectral band. It consists of a group of nine innovative aplanatic dual mirror Imaging Atmospheric Cherenkov Telescopes of 4 m diameter. The telescopes will be installed at the Teide Astronomical Observatory of the Instituto de Astrofisica de Canarias in Tenerife (Canary Islands, Spain) based on a host agreement with INAF. Thanks to its expected overall performance, better than those of current IACT arrays, for energies above about 5 TeV and up to 100 TeV and beyond, the ASTRI Mini-Array will represent an important instrument to perform deep observations of the Galactic and extra-Galactic sky at these energies with high angular resolution (a few arcmins). It will be complementary to the wide-field particle shower arrays (based on water Cherenkov and scintillator detectors) like HAWC and LHAASO already operated in the North hemisphere.
The ASTRI Mini-Array is currently under construction. The site infrastructure, including telescope foundations, data and power network, data center, and control room, will be completed by the end of June 2022. The first telescope of the array (ASTRI-1) has been realized and is currently being tested at the premises of the EIE GROUP company in Italy. It will be integrated at the Tenerife site starting in mid-June, with optical commissioning performed during summer 2022. First tests with a reduced version of the onsite information and communication technology are in progress. The second and third telescopes of the array and the first Cherenkov camera will follow by the end of 2022. We plan to complete the array by 2024. In this paper, we will present the status of the ASTRI mini-array, discussing its design and expected performance.
An EU supported Design Study has been carried out during the years 2018-2021 of how the 5 MW linear accelerator (linac) of the European Spallation Source under construction in Lund, Sweden, can be used to generate a world-uniquely intense neutrino beam for precision measurement of the CP violating phase δCP. As there are definite limits, related to uncertainties in neutrino-nucleus interactions modelling, to by how much the systematic errors in such measurements can be reduced, the way to increase the precision with which δCP can be measured is to make the measurements at the second oscillation maximum, where the CP violation signal is close to 3 times larger than at the first. As the second maximum is located further away from the neutrino source, a higher beam intensity and thus higher proton driver power is required when measuring at the second maximum. The uniquely high power of the ESS linac will allow for the measurements to be made at the second oscillation maximum and thereby for the most precise measurements to be made of δCP. One part of the program, still to be designed, will be to use a Low Energy nuSTORM racetrack ring and a Low Energy Monitored Neutrino Beam to generate beams of both electron and muon neutrinos and measure their cross-sections in the low neutrino energy range with the aim to increase the measurement precision further. In this talk will be described the results of the work made on the design of the main components of the ESSnuSB research infrastructure, which are the ESS linac upgraded to 10 MW, the pulse accumulator ring, the target station, the near neutrino detector and the far neutrino detector, as well as the results of the evaluation of the physics performance for leptonic CP violation discovery and, in particular, the precision with which it will be possible to measure the CP violation phase δCP.
The High Energy Stereoscopic System (HESS) is an array of five imaging atmospheric Cerenkov telescopes (IACTs) to study gamma-ray emission from astrophysical objects in the Southern hemisphere. It is the only hybrid array of IACTs, composed of telescopes with different collection area and footprint, individually optimised for a specific energy range. Collectively, the array is most sensitive to gamma rays in the range of 100 GeV to 100 TeV. The array has been in operation since 2002 and has been upgraded with new telescopes and cameras multiple times. Recent hardware upgrades and changes in the operational procedures increased the amount of observing time, which is of key importance for time-domain science. H.E.S.S. operations saw record data taking in 2020 and 2021 and we describe the current operations with specific emphasis on system performance, operational processes and workflows, quality control and (near) real-time extraction of science results. In light of this, we will briefly discuss the early detection of gamma-ray emission from the recurrent novae RS Oph and alert distribution to the astrophysics community.
KM3NeT is a research infrastructure housing two underwater Cherenkov detectors located in the Mediterranean Sea. It consists of two configurations which are currently under construction: ARCA with 230 detection units corresponding to 1 cubic kilometre of instrumented water volume and ORCA with 115 detection units corresponding to a volume of 7 Mton. The ARCA (Astroparticle Research with Cosmics in the Abyss) detector aims at studying neutrinos with energies in the TeV-PeV range coming from distant astrophysical sources, while the ORCA (Oscillation Research with Cosmics in the Abyss) detector is optimised for atmospheric neutrino oscillations studies at energies of a few GeV. Both detectors are using an innovative multi-PMT design of the optical modules which greatly improves their detection capability. In this talk we present the status of ARCA and ORCA focusing on the technological achievements of the experiment. We also discuss the results obtained using data taken with the first detection units, thus demonstrating the potential of each configuration.
MAGIC is a system of two 17-m diameter Cherenkov telescopes operating at the Observatorio del Roque de Los Muchachos in La Palma (Canary Islands, Spain) since 2009. The telescopes detect very-high-energy (VHE, E > 100 GeV) gamma rays ranging from few tens of GeV to few tens of TeV. In this contribution I will present a selection of the latest scientific results obtained by the MAGIC telescopes, regarding Gamma-Ray Bursts observations, multi-messenger and multi-wavelength astronomy, and the discovery of VHE gamma-ray emission from the first VHE nova, RS Ophiuchi
The Cherenkov Telescope Array (CTA) is the next generation ground-based gamma-ray astronomy observatory, planned to comprise two arrays of imaging air Cherenkov telescopes (IACTs) located in the northern and southern hemispheres. Three telescope sizes are required to cover the CTA gamma-ray energy range from 20 GeV to 300 TeV.
An array of several tens of Small-Sized Telescopes (SSTs) at the southern site situated in the Andes at Paranal in Chile, will provide unprecedented sensitivity above 1 TeV and up to 300 TeV, and offer the highest angular resolution of any instrument at these energies. Following a down selection from three prototype telescopes, the design finally selected for SST comprises a dual mirror Schwarzchild-Couder optic with a 4.3 m diameter primary mirror and a 1.8 m secondary mirror imaged by a SiPM-based camera with a ~9° field of view. The dual mirror optics produces a smaller plate-scale aplanatic focal plane allowing a small, low-cost camera to be employed, compared to that required for the conventional single mirror Davies-Cotton IACT design.
The camera comprises an array of 2048 SiPM pixels, configured as 32 sensor and electronics modules each with an 8 x 8 pixel2 tile populated with 6 x 6 mm2 SiPM pixels. Full waveform capture on every channel is provided by the TARGET ASIC which performs the dual function of event triggering and waveform digitization of the full camera at 1 GSample/s.
We describe the finalized SST camera design including its optimization for the production phase of the project anticipated to begin in 2023.
The Schwarzschild Couder Telescope (SCT) is a dual mirror medium-sized telescope proposed for the Cherenkov Telescope Array (CTA), the next-generation very-high energy (from about 20 GeV to 300 TeV) gamma-ray observatory. The SCT design consists of a dual-mirror optics and a high resolution camera with a field of view (FoV) of 8 degrees squared, which will allow exceptional performance in terms of angular resolution and background rejection. A prototype telescope (pSCT) has been installed at the Fred Lawrence Whipple Observatory in Arizona, USA. Its camera is partially equipped and covers a FoV of 2.7°. The pSCT has recently successfully detected the Crab Nebula with a statistical significance of 8.6 standard deviations. The upgrade of the pSCT focal plane is now ongoing, aimed to equip the full camera with upgraded sensors and electronics, enhancing the telescope field of view from the current 2.7° to the final 8°. In this presentation, an overview of the pSCT project and obtained results will be given, together with the camera upgrade status and expected performance.
The Alpha Magnetic Spectrometer (AMS) is a high-energy particle physics magnetic spectrometer installed on the International Space Station (ISS) in May 2011, successfully operating and taking data since then. The goal of the experiment is to carry out precise measurements of cosmic rays in the energy range from GeV/n to TeV/n. AMS includes a Ring Imaging Cherenkov (RICH), which provides a precise measurement of the particle velocity and its charge. The AMS RICH layout follows a proximity focusing design with two radiators: at the center sodium fluoride tiles surrounded by silica aerogel tiles (n = 1.05). The challenges and the experience gained operating the detector in space for more than 11 years will be presented. The impact of the RICH detector in the AMS physics program will be highlighted and the most recent results on light isotopes in cosmic rays (H, He ,Li and Be) will be shown.
Hyper-Kamiokande is a next-generation neutrino experiment that is under construction in Japan. Its multi-decade physics program addresses appealing, unsolved questions in physics, like the discovery of CP-violation in the leptonic sector and searches for proton decay. It will be used to make a long-baseline neutrino oscillation measurement using the upgraded J-PARC accelerator, upgraded T2K near detector, a new Intermediate Water Cherenkov detector and the new far detector. The Hyper-Kamiokande far detector will be the world’s largest underground water Cherenkov detector, with a fiducial volume 8 times the size of the currently running Super-Kamiokande detector. It will be hosted in the Tochibora mine, 295 km away from the J-PARC.
Hyper-Kamiokande’s far detector will have two optically separated volumes. The inner volume will be instrumented with 20,000 new 50 cm photomultiplier tubes (PMTs) that offer significant performance improvements. In addition, approx. 1000 multi-PMT modules will be installed, which will improve the calibration capabilities of the detector. The outer volume will be instrumented with about 8,000 3-inch PMT’s. The readout electronics of the far detector will be placed underwater, and extensive R&D is on-going to ensure high reliability of the developed systems. The talk will present an overview of the photodetection and readout systems of the Hyper-Kamiokande detector. We will also briefly mention additional calibration possibilities thanks to the use of multi-PMT modules.
The LHCb RICH system has undergone a major upgrade during the Long Shutdown 2 of the LHC and it is now ready for operation. The previous incarnation provided excellent hadron identification during runs 1 and 2 of the LHC. The LHCb strategy of having offline quality reconstruction at the High-Level Trigger 2 stage for run 2 posed many calibration challenges that were met successfully. The performance and stability has recently been analysed covering the period 2015-18. The alignment and calibration processes and the particle identification performance will be presented together with the physics impact on the LHCb analyses and some of the lessons learned during the eight years of operation.
In the forward end-cap of the Belle II spectrometer particle identification is provided by a proximity focusing RICH detector with an aerogel radiator (ARICH). Its main purpose is to provide good separation between pions and kaons in the momentum range from 0.5 GeV/c up to 4 GeV/c, and in addition to contribute to the identification of low momentum leptons. Since the start of its operation, Belle II has collected more than 200 fb$^{−1}$ of data. Based on this large data sample studies of several effects impacting the performance of the ARICH detector were carried out. Findings helped us to improve the detector performance, either by implementing new calibration algorithms or improving the method of data reconstruction and to improve the agreement between the measured data and data from detector simulation. We will report on the detector alignment methods, including alignment of its global position, alignment of planar mirrors on the outer edges of the detector, and a novel algorithm for the alignment of aerogel tiles based on the computer vision methods. We have studied very detailed features of the observed Cherenkov ring image and identified their origin, these include photons produced in the photo-detector quartz window and their possible reflections within the photo-detector, photons produced by delta electrons, and a few other effects. We were able to reproduce these effects in the simulation, resulting in a very good agreement between the data and the simulation. In addition, the observed features were included in the calculation of the expected ring image on which the evaluation of the PID likelihood is based. Finally, we will discuss the impact of particles that decay in flight or scatter in the material before entering the ARICH detector on the PID performance. We demonstrate that these particles have a significant contribution to the observed particle misidentification rates and present our efforts to mitigate this adverse effect by trying to identify the cases when the track is extrapolated to the ARICH but no particle actually entered it, based on combining the response of several Belle II sub-detectors.
NA62 is a new generation kaon experiment at the CERN SPS aiming at measuring the branching ratio (BR) of the ultra-rare K+→π+νν decay with 10% accuracy.
One of main challenges of the experiment is the suppression of background decay channels with branching ratios up to 10 orders of magnitude higher than the signal and with similar experimental signatures, e.g. the background from the K+→μ+ν decay, where the muon is misidentified. To provide such suppression, a powerful particle identification (PID) is needed.
A key element of PID in NA62 is the Ring-Imaging Cherenkov (RICH) detector. According to the NA62 requirements, the RICH should identify μ+ and π+ with a muon rejection factor of at least 100. It also measures the arrival time of charged particles with a precision better than 100 ps and is one of the main components of the NA62 trigger system.
The RICH has successfully operated during the 2016-2018 data taking periods, being essential in the measurement of the BR(K+→π+νν). The detector was also used for searches for lepton flavor violation in 3-track kaon decays. The talk is concentrated on the π/μ and π/e separation directly measured with the data for the aforementioned decays.
At the Belle II experiment a Time-of-Propagation (TOP) counter is used for particle identification in the barel region. This novel type of particle identification device combines the Cherenkov ring imaging technique with the time-of-flight and therefore it relies on a precise knowledge of the time of collision in each triggered event. We will present a maximum likelihood based method which we have developed at Belle II for the determination of event collision time from the measured data.
The Time Of internally Reflected CHerenkov (TORCH) detector is a proposed large-area time-of-flight detector, which aims to enhance the particle identification performance of the LHCb detector in the 2--10 GeV/$c$ momentum range. The Cherenkov light pattern in TORCH is a three-dimensional image (in space and time), which is folded by reflections from the sides of the detector modules. This talk will describe the development of pattern recognition algorithms for TORCH and discuss the challenge of reconstructing detector images in the high occupancy environment expected in the phase II upgrade of the LHCb detector. The reconstruction separates different species of hadron using likelihood ratio tests. The probability density function of the TORCH image is computed semi-analytically from the known Cherenkov emission spectrum, and knowledge of the detector optics. This approach has been shown to be robust and provide good separation between hadron species in the momentum range of interest. The image reconstruction and likelihood calculation are well suited to parallelisation and R\&D into implementation on hardware accelerators is ongoing. The expected particle identification performance of TORCH, and potential applications in the LHCb physics programme will also be discussed.
The Electron Ion collider (EIC) will be the ultimate facility to address the internal dynamics played by the quarks and gluons to global phenomenology of the nucleons and nuclei. The essential physics programs greatly rely on an efficient particle identification (PID) in both the forward and the backward region. The forward and the backward RICHes of the EIC have to be able to cover wide acceptance and momentum ranges. In the forward region a dual radiator RICH (dRICH) is foreseen and in the backward region a proximity focusing RICH is foreseen to be employed.
The geometry and the performance studies of the dRICH have been performed and prescribed in the EIC Yellow Report. This prescription has been adopted in the ATHENA proto-collaboration detector scheme and has been integrated to the ATHENA software. The part of our work reports the effort following the call for EIC detector proposals. In this proposed design, as per prescriptions of the EIC Yellow Report, the forward and the backward RICHes cover wide acceptance and momentum range. In the forward region, dRICH performance showed a pion-kaon separation around 1 GeV/c to 50 GeV/c; whereas in the ATHENA scheme the backward region proximity focusing RICH (pfRICH) is designed with a 40 cm proximity gap is enhanced with filled C4F10 to use this RICH also in the threshold mode. This enables an electron-pion-kaon separation around 1 GeV/c to 10 GeV/c.
This contribution will give an overview of the simulation studies of the particle identification performance of both RICHes designed for the proposal of the ATHENA detector. A detailed description of the simulation chain in DD4Hep framework, the reconstruction of the single photon Cherenkov angle, the models of both RICHes, their performances, and technological synergies and the future plans will be addressed in this contribution.
The Large Area Picosecond Photodetector (LAPPD) is a commercially available microchannel plate (MCP) based photon detector that is currently driving the attention of the entire scientific community thanks to its large size, excellent timing resolution of 60 ps or better, high gain and low dark rate. The LAPPD has a large sensitive area of $200\times200~$mm$^2$, making it an attractive device for RICH detectors at particle colliders, in neutrino experiments, but also in medical imaging and nuclear non-proliferation.
We report on the performance of a new generation-II LAPPD, which is readout by capacitively coupling the signal onto an $8 \times 8$ array of square pixels. Measurements of the time resolution, gain and dark count in the laboratory will be presented.
With its excellent time resolution, the LAPPD is a promising candidate photon detector for the Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment where a future LHCb Upgrade II is foreseen at the beginning of the next decade in order to operate the experiment at the full instantaneous luminosity available in the high luminosity phase of the Large Hadron collider. We will also discuss applications for LAPPDs for neutrino detection in water Cherenkov detectors and in medical imaging.
The next-generation nuclear physics facility in the United States will be the Electron-Ion Collider (EIC), scheduled to be built at Brookhaven National Laboratory (BNL).
%The EIC will be a powerful new high-luminosity facility with the capability to collide high-energy electron beams with high-energy proton and ion beams, providing access to those regions in the nucleon and nuclei where their structure is dominated by gluons. Excellent particle identification (PID) is one of the key requirement for the EIC central detector. Identification of the hadrons in the final state is critical to study how different quark flavors contribute to nucleon properties. A detector using the Detection of Internally Reflected Cherenkov light (DIRC) principle, with a radial size of only 7-8 cm, is a very attractive solution to meet these requirements. The R$\&$D program performed by the EIC PID collaboration (eRD14 and eRD103) is focused on developing a high-performance DIRC (hpDIRC) detector that would extend the momentum coverage well beyond the state-of-the-art 3 standard deviations or more separation of $\pi/K$ up to 6~GeV/$c$, and contribute to low momentum $e/\pi$ separation. Key components of the hpDIRC detector are a 3-layer compound lens and small pixel-size photo-sensors. Currently, the hpDIRC R&D program is focused on developing and validating the radiation hard 3-layer lens, quality assurance of the BaBar DIRC radiation bars, and the early stage of the hpDIRC prototype program with Cosmic Ray Telescope at Stony Brook University, in preparation for beam tests at Fermilab in 2023 and 2024.
The Compressed Baryonic Matter (CBM) experiment is being built at the future Facility for Antiproton and Ion Research (FAIR) next to GSI, Darmstadt, Germany. The fixed-target CBM experiment will explore dense baryonic matter at moderate temperatures produced in A+A collisions at beam energies from 2-11 AGeV. In the matter being created in this collision process, conditions are achieved as they are present in mergers of neutron stars. A key diagnostic probe in order to characterize this matter created in the laboratory is electromagnetic radiation from the fireball, e.g. giving access to its temperature or its lifetime. In CBM, virtual photons will be measured through the reconstruction of di-electrons, the electrons being identified with a gaseous RICH detector and several layers of TRD detectors.
The CBM RICH detector is under development since long, and recently passed the threshold to construction with first mass production of part of the electronics. A full-size prototype of one of the two photodetector planes is under construction in order to test the mechanical stability, handling and the air-cooling concept. Approximately half of the H12700 MAPMTs are temporarily in operation in the upgraded HADES RICH detector. The DiRICH based readout chain now running in HADES has been commonly developed and will also be integrated in CBM. However, in contrast to the triggered HADES readout, CBM will be operated with a free-streaming readout where all detectors send their data with precise time stamps to a central GPU farm for event building and trigger decision. This way, interaction rates of up to 10 MHz will be recorded. In order to test this novel readout concept, a "mini-CBM" (mCBM) experiment has been set up with prototypes of all CBM subdetectors implementing the full functionality of the future free-streaming readout already here. For this purpose a "mini-RICH" (mRICH) detector has been constructed in a proximity focussing geometry using aerogel tiles as radiator. The DiRICH readout has successfully been adopted to the free-streaming CBM readout making use of microtimeslices readout by regular triggers. Recorded data are used to develop AI based noise reduction and ring finding algorithms which will be compared to the so far used Hough Transform.
In this report, a brief update on the development and status of the CBM RICH detector will be given. Main focus of the talk will however lie on the successful construction, operation and characterization of the mRICH detector with free streaming readout. The performance will be evaluated with data recorded in several beamtimes at GSI FAIR phase 0.
The Time Of internally Reflected CHerenkov detector (TORCH) is a proposed large-area time-of-flight detector, which aims to enhance the particle identification performance of the LHCb experiment in the 2–10 GeV/c momentum range. A TORCH module consists of a 10 mm thick quartz plate in which the positions and arrival times of Cherenkov photons from a charged track are detected by highly segmented MCP-PMTs. A general overview of TORCH and its operating principles will be presented, which will then be highlighted by the excellent performance of a 1.25 m length TORCH prototype module (Proto-TORCH). This was equipped with two MCP-PMTs and exposed to an 8 GeV/c test-beam at CERN. Single-photon timing resolutions of between 70-110 ps have been measured, dependent on the beam position in the plate, and photon yields agree with expectations. Another test-beam period has been scheduled for autumn 2022 when the existing TORCH optics will be equipped with a full complement of MCP-PMT detectors and readout, allowing a full system test to be made. Finally, the projected PID performance of TORCH at the LHCb experiment will be shown.
The Super c-Tau Factory is the project of future electron-positron colliding beam experiment with unprecedented high luminosity $10^{35}cm^{-2}s^{-1}$ in the interaction energy range from 3 to 7 GeV, where the most part of charmonium states are produced and the tau-lepton production threshold is located as well. To provide a such high luminosity the Crab-Waist (CW) scheme of beam interaction was suggested. The main goals of the project are to make precise tests of the standard model (SM) and search for the phenomena beyond the SM with statistic exceeded in few orders of magnitude all data accumulated in previous experiments in this energy range. To perform a broad Physics program of the project the high performance universal detector is needed. The current status of R&D on particle identification system for the SCTF project based on Focusing Aerogel RICH (FARICH) is presented as well as a brief description of the SCTF project status. The FARICH is a very powerful particle identification technique. The FARICH detector based on 4-layer focusing aerogel monolithic radiator with total thickness 36 mm and maximal refractive index n=1.05 is able to provide excellent $\pi$/K-separation up to momentum P=6 GeV/c and mu/pi-separation up to P=1.5 GeV/c. The main disadvantage of the FARICH technique is the relatively high threshold momentum for mu/pi-separation (about P=0.4 GeV/c). For $\mu/\pi$ separation below 0.2 GeV/c it is necessary to use energy loss deposition technique in the track system because particles with such momentum will not reach the dedicated PID system due to magnetic field of detector (about 1.5 T). To provide $\mu/\pi$-separation in the gap between 0.2 and 0.4 GeV/c the FARICH detector with dual aerogel radiator was suggested. The capability of particle separation for dual radiator RICH based on 4-layer focusing aerogel with maximal n=1.05 tile combined with aerogel tile with n=1.1 was studied with help of GEANT4 simulation. New production technology of high transparent aerogels with high optical densities based on small dope of zirconium dioxide to SiO$_2$ aerogels was suggested. Parameters of first ZrO$_2$-SiO$_2$ aerogels were measured and presented. It is shown that such approach allow us to produce aerogel with n=1.12 and light scattering length at 400 nm above than 30 mm. First beam tests results of FARICH based on dual radiator combined of 4-layer focusing tile and tile with n=1.1 are presented.
The hadron particle identification provided by the RICH system in LHCb over a momentum range of 2.6 – 100 GeV/c has been a key element of the success of the experiment and will remain equally important for Upgrade II. With luminosities expected to up 7.5 times those expected for Upgrade I and 75 times those released in the past, maintaining in Run 5 and beyond the same excellent PID performance expected in Runs 3 and 4 and demonstrated in Runs 1 and 2, asks for a substantial improvement in the precision of the measurements of the space and time coordinates of the photons detected in the RICH. It will require a readout strategy with high-resolution timing information and making significant improvements in the resolution of the reconstructed Cherenkov angle, new optical schemes and very light-weight components and a DAQ network and reconstruction farm capable of handling and reducing the enormous data flow. The reconstruction software will also need a major upgrade to benefit from these improvements to the measurements. The key elements towards the realisation of these improvements will be discussed, with a view to the needed R&D, simulation results and basic principles.
The ALICE collaboration is proposing a new apparatus, ALICE 3, to investigate the Quark Gluon Plasma (QGP) properties, exploiting precise measurements of heavy-flavour probes as well as electromagnetic radiation. Electromagnetic probes can give access to the system temperature before hadronization, requiring a novel detector concept aimed at an unprecedented level of purity of the thermal di-lepton signal. e/p and K/p separation up to about 2 GeV/c and 10 GeV/c, respectively, is required. In this context, conceptual studies for the development of a RICH detector for ALICE 3 are ongoing. The proposed baseline layout is a proximity-focusing RICH, using aerogel (n = 1.03 at lph = 400 nm) as Cherenkov radiator and a layer of Silicon Photomultipliers (SiPM) for the photon detection, with an area of about 40 m^2. The proposed detector represents the largest one using this technology. A multi-layer (focusing) aerogel layout, with increasing refractive index, is also considered. If sufficient time resolution can be achieved in the SiPM photons detectors, they can be able to identify charged hadrons via TOF measurements. The detector specifications and performance, obtained by means of dedicated Monte Carlo simulation, will be presented. The design and R&D challenges will be also discussed.
C4F10 in COMPASS RICH-1
A Liberec-Prague-Trieste collaboration
Abstract:
COMPASS RICH-1 is using high-purity C4F10 as radiator gas since 2001. The operation and control of the radiator gas has evolved over years with continuous improvements.
We report on the experience gained in the 20 year-long operation of C4F10 as COMPASS RICH radiator.
C4F10 procurement is becoming challenging, and the minimization of material waste is now a priority for the protection of the environment. Commercially available C4F10 needs dedicated filtering before usage and typical material losses in the filtering procedure are around 30%. Recent efforts allowed to reduce them to about 5%.
Very accurate values for the radiator gas refractive index are needed for high-performance particle identification. The procedure has evolved over years and the one presently in use, which provides refractive index estimate at the 1 ppm level, is discussed.
A new system, based on a modified folded Jamin interferometer, has been recently built. It will provide very precise online monitoring of the COMPASS RICH-1 gas radiator refractive index.
Aerogel radiators for Cherenkov detectors have been produced in Novosibirsk by a collaboration of Budker Institute of Nuclear Physics (BINP) and Boreskov Institute of Catalysis (BIC) for more than three decades. Over this time aerogel radiators were manufectured for different threshold Cherenkov detectors (KEDR, SND experiments at BINP; DIRAC at CERN) and Ring Imaging Cherenkov detectors (AMS-02, LHCb, CLASS12 experiments). Production of raw aerogel tiles is conducted in BIC.
In this work we present our experience in the characterization, selection and mechanical processing of aerogel tiles. The following physical parameters are measured: refractive index, variations of the refractive index, the light scattering length, the light absorption length. The index of refraction of the blocks is controlled through their density. The variations of the index of refraction within tile volume are measured using digital X-ray detector. The light scattering length is measured through the transparency dependence on the light wavelength. To control the light absorption length several specialized stands have been developed.
Aerogel tiles can be machined using different technologies to fit the case of Cherenkov detector. For this work we use polishing machine, diamond wheel and diamond wire cutting machines.
The silicon dioxide aerogel we produce is hygroscopic. It requires special dry storage conditions. If needed, after aerogel characterization and processing the absorbed water could be removed from aerogel tile using annealing. This procedure restores initial optical parameters.
Excellent particle identification is an essential requirement for the future Electron Ion Collider (EIC) experiment. Particle identification (PID) of the final state hadrons in the semi-inclusive deep inelastic scattering allows the measurement of flavor-dependent gluon and quark distributions inside nucleons and nuclei. The EIC PID Consortium (eRD14 Collaboration) was formed in 2015
for identifying and developing PID detectors using ring imaging Cherenkov(RICH)
and the ultra-fast time-of-flight (TOF) techniques for the EIC experiments
with broad kinematics coverage.
To meet the challenge of limited confined space of electron end-cap in the EIC experiments, a compact modular ring imaging Cherenkov (mRICH) detector has been developed that provides $K/\pi$ separation over a momentum coverage of 2 GeV/$c$ to 8 GeV/$c$ , and an $e/\pi$ separation up to 2 GeV/$c$ or more. The mRICH detector consists of an aerogel block, a Fresnel lens, photosensor plane and flat mirrors forming the sides of the space between the lens and photosensors. The first prototype of this detector was successfully tested at Fermi National Accelerator Laboratory (FNAL) in April 2016 for verifying the detector work principles.This was followed by a second prototype test in 2018 at FNAL with much improved optical design and photosensor integration, which allowed adaptation of different readout options. In September 2021, the third beam-test was carried at Jefferson Laboratory (JLAB) with the goal of testing mRICH performance with a precision tracking capability.
The housing of the sensors for future RICH detectors is a complex task, regardless of the sensor choice,
due the many requirements. In order to save on the required resources and simplify the design, different
functions should be possibly integrated all together, including, for SIPM-like sensors, some sort of active
cooling. A local cooling strategy is being investigated first, to cool down a region as small as possible around
the sensor only, exploiting the industrial technologies existing today for cooling of solid state devices by
many applications. The results of test conducted so far will be presented together the current conceptual
design, tests and prototyping.
The prompt Cherenkov radiation and focusing optics of the LHCb RICH detectors allow the prediction of the Cherenkov photon detection time from a given track to within ten picoseconds. Fast-timing information on the detected Cherenkov photons can therefore be used to significantly improve the PID performance and the signal-to-noise ratio of the detectors. This concept is a cornerstone for the LHCb RICH detector upgrades and will ultimately allow the system to operate at a luminosity in excess of $10^{34}\,$cm$^{-2}\,$s$^{-1}$ during HL-LHC Run 5. The motivation and concepts behind the detector enhancements during Long Shutdown 3 (LS3, 2026-2028) and the proposed new electronic readout chain will be presented. The specifications for the new ASIC called the FastRICH will be discussed in the context of the LS3 enhancements and LHCb Upgrade II. The FastRICH ASIC will perform multi-channel single-photon discrimination, timestamp photons with 25 ps bin size, integrate closely with the LHCb optical link chipset and apply data-compression techniques. It will allow the system to timestamp each photon with an ~150 ps resolution (dominated by the existing MAPMT transit time spread) within a short gate of ~2 ns (the time spread from the LHCb collisions). The new electronic readout chain introduces important timing and detector techniques ahead of the Upgrade II RICH system overhaul and the FastRICH has the flexibility to be coupled to sensors with better time resolution for HL-LHC Run 5. Simulation studies have demonstrated improvements in the hadronic PID performance during Run 4 using the FastRICH and the current photon detectors. A first version of the readout chain, based on the FastIC, a predecessor of the FastRICH ASIC, and a TDC-in-FPGA, has been studied using Cherenkov photons at the CERN SPS charged particle beam test facility. The readout chain was coupled to MAPMT and SiPM sensors. The results will be presented and interpreted in the context of the RICH detector future upgrades.
The COMPASS RICH-1 detector has undergone a major upgrade in 2016 with the installation of four novel MPGD-based photon detectors. They consist of large-size hybrid MPGDs with multi-layer architecture composed of two layers of Thick-GEMs and bulk resistive MicroMegas. A dedicated high voltage power supply system has been built and put in operation. It controls more than 100 HV channels. The system is required to protect the detectors against errors by the operator, monitor and log voltages and currents at a 1 Hz rate, and automatically react to detector misbehavior. It includes also a sophisticated HV compensation system against environmental pressure and temperature variation. In fact, voltage compensation is always a requirement for the stability of gaseous detectors and its need is enhanced in multi-layer ones. In particular, the needs posed to high voltage power supply systems by the operation of Micro Pattern Gaseous Detectors in terms of high-resolution diagnostic features and intelligent dynamic voltage control are required both when technology development is performed and when extended detector systems are supplied and monitored. Systems satisfying all the needed features are not commercially available.
A single channel high voltage system matching the Micro Pattern Gaseous Detector needs has been designed and realized, including its hardware and software components.
In this talk the COMPASS HV system and its performance are illustrated, as well as the stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS. As further development, the design, implementation and performance of a HV channel based on DC to DC converter and controlled by a FPGA system is presented. The performance of the single channel power supply when connected to a Micro Pattern Gaseous Detector in realistic working condition during a test beam will be shown
Presentation of the posters, in the following order:
Joao Pedro Athayde Marcondes De Andre
Neutrino mass ordering determination through combined analysis with JUNO and KM3NeT/ORCA
Emily Baldwin
Simulating the Effect of External Magnetic Fields on Microchannel Plates
Alessandro Petrolini
Optical Systems For Future RICH Detectors
Lucian Nicolae Cojocariu
A 32-channel TDC Implemented on an FPGA for Photodetector Timing Studies
Carmen Giugliano
Quality Assurance procedures for the LHCb RICH Upgrade
Floris Keizer
From the FastIC ASIC to FastRICH, A Readout Chip for the Upgrade of the LHCb RICH Detector
Steven Leach
Characterisation of Cherenkov Optimised Silicon Photomultipliers Following Long Duration Operation
Andrej Lozar
Study of new aerogel radiators for the LHCb RICH upgrade
Davide Mollica
MUCH: a compact Imaging Atmospheric Cherenkov Telescope for volcano muography
Anja Novosel
Image Based Particle Identification at Low Momenta
Stephan O'Brien, David Hanna
Calibration of the Aerogel radiator tiles for the RICH of the HELIX Experiment
Rok Pestotnik
Slow control of the Belle II Aerogel Ring Imaging detector
Pavish Subramani
Qualification of DIRICH readout chain
Umberto Tamponi
STOPGAP - a Time-of-Flight Extension for the Belle II TOP Barrel PID System
Simone Vallarino
The dual Ring Imaging Cherenkov detector for the Electron-Ion Collider
Zoom connection
Gayane Ghevondyan
ARICH performance study in the Belle II experiment
Ivan Sidelnik
The capability of water Cherenkov detectors arrays of the LAGO project to detect Gamma-Ray Burst and High Energy Astrophysics sources
Ticiano Jorge Torres Peralta
Particle Classification in the LAGO Water Cherenkov Detectors using Clustering Algorithms
Luis Otiniano
Measurement of the Muon Lifetime and the Michel Spectrum in the LAGO Water Cherenkov Detectors as a tool to improve energy calibration and to enhance the signal-to-noise ratio
Special mention
Elena Cherenkova
Details of the study of the superluminal electrons
Silicon photomultipliers (SiPM) are candidates selected as the potential photodetector technology for the dual-radiator Ring-Imaging Cherenkov (dRICH) detector at the future Electron-Ion Collider (EIC). SiPM optical readout offers a large set of advantages being cheap devices, highly efficient and insensitive to the high magnetic field (~ 1.5 T) at the expected location of the sensors in the experiment. On the other hand, SiPM are not radiation tolerant and despite the integrated radiation level is expected to be moderate (< 10¹¹ 1-MeV neq/cm2) it should be tested whether single photon-counting capabilities and the increase in Dark Count Rate (DCR) can be kept under control to maintain the optimal dRICH detector performance across the years.
Several options are available to maintain the DCR to an acceptable rate (below ~100 kHz/mm2), namely by reducing the SiPM operating temperature, using the timing information with high-precision TDC electronics, selection cuts based on bunch crossing information, and by recovering the radiation damage with high-temperature annealing cycles.
In this presentation we present the current status of the research and the first results on studies performed on a large sample of commercial (Hamamatsu) and prototype (FBK) SiPM sensors. The devices have undergone an irradiation campaign where an increasing NIEL dose up to 1011 1-MeV neq/cm2 has been delivered to different sensor subsets. The sensors have then undergone high-temperature annealing cycles to recover the radiation damage. The results obtained with a complete readout system based on the first 32-channel prototypes of the ALCOR ASIC chip are also reported. Measurements are performed in a controlled-temperature environment where the sensors are mounted in a climatic chamber for characterisation. The setup is also equipped with a movimentation system and a pulsed LED light source to further test the response of multiple sensors and compare the performance of new sensors with the one of irradiated sensors. The time coincidence between the recorded SiPM light signal and the generated LED pulse is used to further discriminate dark-count signals from light signals.
Figure 1: Special care has been used to design a SiPM-carrier board with high-temperature resisting components and an edge connector to cope with temperatures as high as 180 C. (left) One of the custom prototype SiPM boards designed for the irradiation and high-temperature annealing campaign. The shaded area shows the region of the delivered uniform radiation field. (centre) Gafchromic film impressed by the collimated proton beam delivered by the setup shown installed at the TIFPA Trento Protontherapy Centre Irradiation Facility, demonstrating the uniform 3 mm vertical irradiation field. Special care has also been put in the design and realisation of a collimation system with micrometric movimentation to allow us to precisely deliver the proton beam in a 3 mm vertical slit with uniform radiation field. (right) Ratio of the measured current to the current measured on brand new sensor at fixed bias voltage as a function of the level of NIEL delivered radiation, before and after high-temperature annealing.
Figure 2: Measurements of the dark-count rate (DCR) performed with the full readout system coupled to the ALCOR ASIC chip. (left) Single-photon counting is demonstrated by the step-ladder behavior of the DCR as a function of the ALCOR ASIC discriminator threshold for SiPM irradiated up to 10¹¹ NIEL after the annealing cycle. The figure shows a sensor that has received 10¹⁰ 1-MeV neq/cm² NIEL, although similar behavior with higher rates is observed for higher delivered NIEL. (right) A comprehensive measurement of the DCR for the large sample of new and irradiated Hamamatsu SiPM sensors shows great uniformity in the response up to the highest delivered dose. The curves show the DCR as a function of the bias voltage at fixed ALCOR ASIC discriminator threshold (1-pe) for new sensors (blue) and irradiated sensors (red) with increasingly delivered NIEL. The width of the bands represent the dispersion of the rates measured in the large sample of sensors characterised.
Figure 3: Studies with pulsed LED light. (left) The complete prototype readout system inside the climatic chamber mounted on the XY movimentation system in front of the fixed LED light source. The readout system comprises the SiPM matrix carrier board mated with the adapter board, both visible in the picture. The adapter board is coupled with the ALCOR Front-End board which is on the back of the adapter board. The system hosts two SiPM boards, one on the left-hand side with a limited number of sensors which is used as reference for LED light stability checks and one full board for characterisation. (right) Time coincidence between the recorded SiPM light signal and the generated LED pulse.
An optimized design and process flow in a specialized 350 nm CMOS technology yields Single-Photon Ava-lanche Diodes (SPADs) with extremely low Dark Count Rates (DCR). They show optimal properties for de-tecting visible and near infrared photons in low quantity with high timing resolution. These characteristics are crucial for building up Silicon Photomultipliers (SiPM) to detect Cherenkov radiation in particle detection and astrophysics. SPAD-based SiPM typically excel photomultiplier tubes (PMT) with regard to detection efficiency, integration possibilities and their tolerance of magnetic fields, struggle, however, with a higher noise level, introduced by the DCR [1]. The presented SPADs show extremely low DCR values of 2·10-4 cps/µm² at 260 K down to 4·10-8 cps/µm² (= 0.04 cps/mm2) at 160 K [3] and thus can outperform PMTs in demanding detection applications.
A novel technology for 3D integration using direct bonding of 8” wafers was developed to allow a highly compact and integrated combination of low-noise backside-illuminated SPADs with circuits fabricated in advanced CMOS nodes achieving high readout speed and timing resolution. Customized through-silicon vias (TSV) establish the electrical interconnection of sensor and readout wafers for each individual SPAD. Utilizing this technology, a versatile SPAD-based detector with photon timing as well as counting capabili-ties was developed and successfully applied in LiDAR (Light Detection and Ranging), quantum imaging and quantum number generation [2]. This technology enables integration of high-performance circuits to en-hance the digital SiPM and could make separate front-end-electronic ASICs in detection modules redun-dant. Additionally, multiple techniques in CMOS processing as well as post-processing are shown to en-hance the detection probability and efficiency in specific spectral regions to optimize the performance for various applications.
The combination of these technologies promises great potential for highly integrated, low-noise, efficient and high-resolution digital SiPM. High flexibility in design, improvements by CMOS- as well as post-processing and the availability of a reliable 3D integration technology enable a viable path towards small to medium volume fabrication of enhanced detectors for Cherenkov radiation.
PANDA is one of the main experiments at the FAIR facility at GSI which will study different aspects in QCD by, e.g., performing hadron spectroscopy, among others in searching for glueballs and exotic states, and by investigating hyperons. The PANDA experiment will use an antiproton beam in the momentum range of 1.5 to 15 $\mathrm{GeV/c}$ colliding with a stationary target. Due to antiproton-proton annihilations the production of exotic particles and states is directly possible. The PANDA detector consists of a target and forward spectrometer. Two DIRC detectors, a cylindrically shaped Barrel DIRC (BaD) around the interaction region and an Endcap Disc DIRC (EDD) covering the forward hemisphere, will be used for particle identification in particular for $\mathrm{\pi/K}$ separation up to 4 $\mathrm{GeV/c}$.
Since the focal planes of both DIRC detectors will reside in an $\sim$ 1 T magnetic field and because of other boundary conditions microchannel-plate photomultipliers (MCP-PMTs) are the only viable sensor candidates. Their advantageous properties in terms of excellent time resolution, moderate dark count rate and especially their favorable gain behavior inside magnetic fields make them most suitable for the PANDA DIRCs. During a planned PANDA operation time of $\sim$10 years at full luminosity the MCP-PMTs have to withstand $>$5 $\mathrm{C/cm^{2}}$ integrated anode charge without any QE losses. Previous aging problems of MCP-PMTs were recently solved by applying the ALD (atomic layer deposition) coating technique. For this matter an ultrathin layer of alumina or magnesia covers the MCP glass substrate leading to an increased MCP-PMT lifetime of up to a factor $\sim$100. The current status of these measurements will be presented. Furthermore the sensors have to be capable to detect single photons at very high rates [$\sim$0.2 MHz/cm$^{2}$ (BaD) and up to 1 MHz/cm$^{2}$ (EDD)].
To measure these and other performance parameters by surface scans a semi-automatic setup was built, consisting of a light tight and copper shielded box combined with a 3-axis stepper and a picosecond laser pulser. With the multihit capable, FPGA-based DiRICH/TRB (Trigger and readout Board) DAQ many parameters like time resolution, dark count rate, afterpulsing ratio, charge sharing crosstalk and electron recoil behavior, but also QE and gain homogeneity, can be simultaneously obtained as a function of the xy-position. This paper will present new insights to the performance parameters of several types of the very latest multi-anode MCP-PMTs. In particular properties like gain and internal parameters like charge cloud width and electron recoil distributions were investigated also inside the magnetic field. In addition the performance of new MCP-PMTs from Photonis with an anode layout of 3 $\times$100 pixels will be shown in this talk. Also recently observed side effects with the latest two ALD layer MCP-PMTs will be reviewed.
Researchers at IHEP have conceived two types of MCP-PMTs for the photon detection in particle physics. One is the 20 inch Large MCP-PMT (LPMT) with small MCP units in the large area PMTs for the neutrino detection. This LPMT has already been mass produced more 15K pieces in the JUNO experiment, and has also been evaluated by the PMT group in LHAASO and HyperK. The other is the 2 inch Fast MCP-PMT (FPMT) with the fast timing resolution for particle identification in the collider detector. The FPMT prototypes have been produced with 50 ps time resolution, and also the 8X8 readout anode for the position resolution. This talk will introduce the two types of MCP-PMT and their performance tested in the lab.
Photek have developed a square microchannel plate (MCP) PMT using 6 µm pore MCPs to achieve superior timing, compared to the previous generation which used 15 µm pores. The native anode pattern is 64x64, but for this module the pattern is ganged to a 16x16 design using an epoxy bonded PCB giving an anode size of 3.3×3.3 mm2 in a 53×53 mm2 active area. The electronic front-end is the TOFPET2d ASIC from Petsys Electronics, a combined amplifier / discriminator / TDC with 30 ps time bins and capable of 480 kHz per channel count rate, with sufficient dynamic range to allow for the gain variation inherent in large area MCP-PMTs. Communications is through gigabit ethernet. The outer envelope of the combined PMT and electronic front-end package allows for close packing on 4 sides with outer dimensions of 60×62 mm giving a 76% fill factor. We present results showing the uniformity of detection efficiency, single photon timing accuracy and count rate capability. All data is taken on PMTs with ALD coated MCPs capable of > 5 C/cm2 accumulated lifetime.
The BelleⅡ experiment is a high luminosity electron and positron collider experiment at SuperKEKB in Japan. In this experiment, we aim to measure B-decay precisely and search for effects from New Physics. We started physics data taking with the whole detector system in March 2019. The Time-of-propagation (TOP) counter is a detector for particle identification in the barrel region of the BelleⅡ detector. It consists of a quartz radiator and high timing resolution photodetector, and it can identify $K^{\pm}$ and $\pi^{\pm}$ from the arrival time and hit position of Cherenkov light.
Micro-Channel-Plate Photomultiplier(MCP-PMT) is the photodetector for the TOP counter; it measures photon timing with a resolution of 30 ps; it gives excellent particle identification performance. One of the issues for the TOP counter is the lifetime of the photocathode of MCP-PMTs. The quantum efficiency (QE) will decrease by the accumulated output charge of MCP-PMTs due to the outgassing from MCPs. We have worked to improve the lifetime of the photocathode and installed three types, Conventional type, Atomic Layer Deposition (ALD) type, and Life-extended ALD type, in the TOP counter. The lifetime of the conventional MCP-PMT is 1.1 $\mathrm{C/cm^2}$ on average, and we are planning to replace it with the Life-extended ALD type that has the longest lifetime during the long shutdown that starts in 2022 summer.
We have developed monitoring tools for MCP-PMTs and measured the gain, output charge, and QE of MCP-PMTs during physics data taking. First, we measured the gain, and it changed about 10$\%$ during physics data taking due to the characteristics of ALD that applied to MCP for a longer lifetime. To make the output charge of MCP-PMTs smaller, we are operating with relatively low gain. Due to this, threshold efficiency will decrease during physics data taking. We increased the high voltage for MCP-PMTs during physics data taking, considering gain decrease and output charge to keep efficiency. Second, we measured the output charge of MCP-PMTs. ( Figure1 ) These are small enough compared to their lifetime, and we expect that there is almost no QE degradation in all MCP-PMTs. Finally, we measured the QE degradation considering the threshold efficiency drop during the physics data taking. ( Figure2 ) As a result, we found a more considerable QE degradation than expected in 5$\%$ of MCP-PMTs. We think this degradation is a problem of the MCP-PMT production, noise from the read-out system, etc.
We will present the MCP-PMT status and the operation status of the TOP counter at the BelleⅡ experiment.
The development of a single-photon detector based on a vacuum tube, transmission photocathode, microchannel plate and CMOS pixelated read-out anode is presented. This imager will be capable of detecting up to 1 billion photons per second over an area of 7 cm$^2$, with simultaneous measurement of position and time with resolutions of about 5 microns and few tens of picosecond, respectively. The detector has embedded pulse processing electronics with data-driven architecture, producing up to 160 Gb/s data that will be handled by a high-throughput FPGA-based external electronics with flexible design. These performances will enable significant advances in particle physics, in particular for the realisation of future Ring Imaging Cherenkov detectors, capable of achieving high efficiency particle identification in environments with very high particle multiplicities, exploiting time-association of the photon hits at the level of tens of picoseconds.
The upgraded LHCb RICH detectors are equipped with Multianode Photomultiplier Tubes, covering a total area of approximately 4 square metres. In order to achieve the same excellent hadron identification performance as during LHC Run 1 and 2 at five times the instantaneous luminosity, the photon detectors have to be sensitive to single photons with repetition rates of up to $100~\text{MHz/cm}^2$ and to have a very low noise count rate.
The main properties of the photomultipliers are presented, together with the characterisation of an unexpected source of noise observed in the Hamamatsu R11265 Multianode Photomultiplier Tubes, extending up to several microseconds after the primary signal. The quality control results and the mitigation strategies to operate the photon detectors and to perform optimal single-photon counting at 40 MHz are described.
Progress on coupling MPGD-based photon detectors with nanodiamond photocathodes
A Bari-Trieste Collaboration
Abstract:
Hydrogenated nonodiamond grains represent an alternative to CsI for detection of single VUV photons in gaseous detectors. A dedicated R&D study on the performance of nanodiamond photocathodes coupled to THGEM-based photon detectors is ongoing.
The first phase of these studies includes the comparison of QE in vacuum and in gaseous atmospheres and measurement of aging effects under irradiation and exposure to moisture: promising values for the VUV sensitivity and high robustness have been observed.
The second phase consists in the characterization of the performance as electron multipliers of THGEMs coated with a variety of nanodiamond photoconverting layers: preliminary encouraging results from the ongoing systematic studies have been obtained.
For the third phase, a photon detector prototype with hybrid Micromegas and THGEMs architecture has been built and equipped with hydrogenated nanodiamond photocathode on the first THGEM layer.
We report on the status and perspective of this R&D programme.