CHEF 2017

2 Oct 2017, 10:00 → 6 Oct 2017, 17:00 Europe/Paris

Other Institutes

CHEF2017 is the second edition of the CHEF conferences serie that started in 2013 with the goal to address the calorimeters at the energy frontiers in Physics. It also deals with the innovative concepts of calorimetry in nuclear, particles and astroparticles physics. Calorimeter concepts go beyond the detection aspects and therefore CHEF gives an important place to discuss the measurement, simulation techniques as well as electronic readout system and services in the calorimetry field.

Monday, 2 October

Institutional: Welcome

1 Welcome to CHEF

Speaker: Imad Laktineh (Universite Claude Bernard Lyon I (FR))

CHEF2017welcome.pdf

CHEF2017welcome.pptx

2 Welcome to IPNL

Speaker: Guy Chanfray

3 IN2P3 welcome

Speaker: Patrice Verdier (IN2P3)

Calibration & operation

Convener: Bernard Ille (Universite Claude Bernard Lyon I (FR))

4 ATLAS LAr Calorimeter Performance in LHC Run-2

The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to 1034 cm−2 s−1. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic calorimetry in the region from |η| = 1.5 to |η| = 4.9. In the first LHC run a total luminosity of 27 fb−1 has been collected at center-of-mass energies of 7-8 TeV between year of 2010 to 2012. Following a period of detector consolidation during a long shutdown, Run-2 started with approximately 3.9 fb-1 and 35.6 fb-1 of data at a center-of-mass energy of 13 TeV recorded in 2015 and 2016, respectively. In order to realize the level-1 acceptance rate of 100 kHz in Run-2 data taking, number of read-out samples for the energy and the time measurement has been modified from five to four with keeping the expected performance. The well calibrated and highly granular Liquid Argon Calorimeter achieved its design values both in energy measurement as well as in direction resolution, which was a main ingredient for the successful discovery of a Higgs boson in the di-photon decay channel. This contribution will give an overview of the detector operation, hardware improvements, changes in the monitoring and data quality procedures, to cope with increased pileup, as well as the achieved performance, including the calibration and stability of the electromagnetic scale, noise level, response uniformity and time resolution.

Speaker: Elena Yatsenko (Centre National de la Recherche Scientifique (FR))

ATLAS_LAr_Yatsenko.pdf

5 Commissioning of the CMS Hadron Forward Calorimeters Phase I Upgrade

The final phase of the CMS Hadron Forward Calorimeters Phase I upgrade was performed during the Extended Year End Technical Stop of 2016 – 2017. In the framework of the upgrade, the PMT boxes were reworked to implement two channel readout in order to exploit the benefits of the multi-anode PMTs in background tagging and signal recovery. The front-end electronics were also upgraded to QIE10-based electronics which implement larger dynamic range and a 6-bit TDC.

Following this major upgrade, the Hadron Forward Calorimeters were commissioned for operation readiness in 2017. Here we describe the details and the components of the upgrade, and discuss the operational experience and results obtained during the upgrade and commissioning.

Speakers: Yasar Onel (The University of Iowa (US)), Yasar Onel (Physics and Astronomy Department)

CHEF17_Onel_Phase1_v1.pdf

CHEF17_Onel_Phase1_v1.pptx

6 Operation and performance of the LHCb calorimeter system

The LHCb calorimeter system plays a key role in the hardware trigger of the experiment and also serves the measurement of radiative heavy flavor decays and neutral mesons. Placed 12 meters from the interaction region, the system is composed of four elements: a plane of scintillating tiles followed by a pre-shower detector used for particle identification, a shashlik ECAL and a sampling HCAL.

The main part of the talk will be devoted to the presentation of the technical and operational aspects of these detectors. Emphasis will be put on the monitoring and correction of radiation induced effects as well as on the energy calibration. In a second part, the reconstruction of calorimeter objects and the neutral PID tools will be presented. Achieved performance will be reported using benchmark decay modes.

Speaker: Maximilien Chefdeville (Centre National de la Recherche Scientifique (FR))

lhcb_chef.pdf

7 Performance of the CMS precision electromagnetic calorimeter at the LHC Run II and prospects for high-luminosity LHC

Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high resolution electron and photon energy measurements. Particularly important are decays of the Higgs boson resulting in electromagnetic particles in the final state, as well as searches for very high mass resonances decaying to energetic photons or electrons. Following the excellent performance achieved during LHC Run I at center of mass energies of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) is operating at the LHC with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run II has achieved unprecedented levels. The average number of concurrent proton-proton collisions per bunch-crossing (pileup) has reached up to 40 interactions in 2016 and may increase further in 2017. These high pileup levels necessitate a retuning of the ECAL readout and trigger thresholds and reconstruction algorithms, to maintain the best possible performance in these more challenging conditions. The energy response of the detector must be precisely calibrated and monitored to achieve and maintain the excellent performance obtained in Run I in terms of energy scale and resolution. A dedicated calibration of each detector readout channel is performed with physics events exploiting electrons from W and Z boson decays, photons from pi0/eta decays and the azimuthally symmetric energy distribution of minimum bias events. This talk describes the new reconstruction algorithms and calibration strategies that were implemented to maintain the excellent performance of the CMS ECAL throughout Run II. We will show performance results from the 2015-2016 data taking periods and provide an outlook on the expected Run II performance in the years to come. Finally, we review the design and R&D studies for the CMS ECAL crystal calorimeter upgrade for the HL-LHC era, which will include new readout and trigger electronics, and we also present first test beam studies.

Speaker: Zhicai Zhang (California Institute of Technology (US))

CHEF2017_ZhicaiZHANG_CMS_ECAL_final.pdf

Break: Lunch

Exotic

Convener: Toru Takeshita (Shinshu University (JP))

8 The Mu2e undoped CsI crystal calorimeter

The Mu2e experiment at Fermilab searches for the charged-lepton flavour violating neutrino-less conversion of a negative muon into an electron in the field of a aluminum nucleus. The dynamics of such a process is well modelled by a two-body decay, resulting in a mono-energetic electron with an energy slightly below the muon rest mass (104.967 MeV). If no events are observed in three years of running, Mu2e will set a limit on the ratio between the conversion rate and the capture rate \convrate of $\leq 6\ \times\ 10^{-17}$ (@ 90$\%$ C.L.). This will improve the current limit by four orders of magnitude~\cite{MU2ETDR}.

A very intense pulsed muon beam ($\sim 10^{10} \mu/$ sec) is stopped on a target inside a very long solenoid where the detector is located. The Mu2e detector is composed of a tracker and an electromagnetic calorimeter and an external veto for cosmic rays surrounding the solenoid. The calorimeter plays an important role in providing excellent particle identification capabilities, a fast online trigger filter while aiding the track reconstruction capabilities. It should be able to keep functionality in an environment where the n, p and photon background from muon capture processes and beam flash events deliver a dose of ~ 120 Gy/year in the hottest area. It will also need to work in 1 T axial magnetic field and a $10^{-4}$ torr vacuum. The calorimeter requirements are to provide a large acceptance for 100 MeV electrons and reach:
(a) a time resolution better than 0.5 ns @ 100 MeV;
(b) an energy resolution {\it O($10\%$)} @ 100 MeV and
(c) a position resolution of 1 cm.

The calorimeter consists of two disks, each one made of 674 pure CsI crystals read out by two large area array 2$\times$3 of UV-extended SiPM 6$\times$6 mm$^2$. We report here all progresses done for the construction and test of the Module-0 prototype that is an array of 51 pre-production crystals from St.Gobain, Siccas and Amcrys firms. Each crystal has been readout by two pre-production Mu2e SiPMs selected among the ones produced by Hamamatsu, Sensl or Advansid . Each photosensor has been amplified and regulated in bias voltage by means of a FEE custom chip. Final digitization stage is also custom and relies on a 5 ns sampling.

The module-0 has been exposed to an electron beam in the energy range around 100 MeV at the BTF (Beam Test Facility) in Frascati. Preliminary results of timing and energy resolution at normal incidence will be shown as well as dependence on the impact angle.

Speakers: Stefano Di Falco (Universita & INFN Pisa (IT)), Stefano Di Falco (Universita degli Studi di Pisa)

difalco_chef2017.pdf

9 A study of fiber in shashlik calorimeter

A shashlik electromagnetic calorimeter will be produced in Hall A of Jefferson Laboratory for Solenoidal Large Intensity Device (SoLID). WLS fiber and clear fiber will be used as the light guide part of the calorimeter. The blue light from scintillators is converted into green light by WLS fibers and is carried out to the back of the calorimeters for readout. Since the magnetic field reaches about 1.5 T behind the calorimeters, the design is to use clear fibers to further guide the light out of the solenoid for readout by PMTs. Therefore, it is significant to study the perfomance of WLS fiber and clear fiber. This paper describes a comparative test of two different WLS fibers and a light attenuation test for a clear fiber. The results show that the performance of the two WLS fibers is the same under large curvature bending, as well as the attenuation length of the clear fiber is 1.55 dB/m and bending has no effect on clear fiber. Besides, a comparison test for two fiber end-face reflective materials were also described. It reveals that the use of silver ink as a reflective material can increase the light yield by 30%. Thereby, a optimized prototype based on the above experimental results was built and the basic performance were also tested.

Speaker: Chendi Shen (Tsinghua University (CN))

An optimized prototype of Electromagnetic Calorimeter for SOLID

ECal for MPD NICA

10 Response of the DAMPE BGO Calorimeter to Heavy Nuclei

A BGO calorimeter was built for a high energy cosmic ray experiment, named the DArk Matter Particle Explorer (DAMPE), which was launched in the end of 2015. In order to determine the response of the calorimeter to heavy nuclei, an experiment was carried out with 40 and 75 GeV/A ion beam at CERN SPS. The performance of the calorimeter, including quenching effect of the BGO crystal, the energy resolution and the loss of ions due to nuclear interaction, are investigated. Some details about orbit performance are also presented in this report.

Speaker: Yifeng Wei (USTC)

CHEF2017_weiyf.pdf

11 The Telescope Array experiment for researching Ultra High Energy Cosmic Rays.

We will introduce observation technique, future plan and report current results of the Telescope Array (TA) experiment to research Ultra High Energy Cosmic Rays (UHECRs).
The UHECR, highest energetic phenomena in the Universe, is crucially important to solve mysteries in modern astrophysics. The UHECRs can be observed with an Extensive Air Shower (EAS) which is an interaction of UHECR with the atmosphere as a natural calorimeter.
The TA experiment is an observatory to observe the EASs of the UHECRs using two types of detectors. One type is an array by ~500 of surface detectors (SDs) to catch charged particles on the ground, and the other type is 3 stations of fluorescence detector (FD) to observe fluorescence photons emitting from air molecule excited by EAS. Currently, we are expanding aperture 4 times larger with additional 500 of SD and 2 stations of FD, and the branch experiments of TA using Cherenkov emission from EAS and radio scatter by EAS are operating and developing. To monitor the stability of the detectors, we use various on-site calibration systems and facilities, one of the unique facility to generate artificial EAS using electron linear accelerator named ELS. With detectors and calibration system, we can precisely determine properties of UHECR; the energy spectrum, chemical composition, and the arrival direction. Most exciting achievement is finding the event cluster with an energy greater than 57 EeV so-called "GZK energy limit" which is evidence of a possible source of UHECR.

Speaker: Bokkyun Shin (Hanyang University)

BK-TA-CHEF2017-v6.pdf

12 The PADME experiment calorimeters for missing mass dark photon searches

The PADME experiment at the Frascati Beam-Test Facility (BTF) aim at searching for invisible decays of a dark photon A’, by measuring the missing mass in fixed-target annihilations of a positron beam: e+ e-  A’. The measurement requires a precise determination of the momentum of the recoil photon, performed by means of a highly-segmented, high-resolution and low-threshold BGO crystal calorimeter, complemented by a fast, high-efficiency, fast Cherenkov calorimeter, for recovering very small angle photon events, at the same time fighting the Bremsstrahlung and three-photons decay background. Stringent requirements on the efficiency, resolution and timing performance push the design of calorimeters, also from the point of view of mechanical construction, readout and calibration.

Speaker: Fabio Ferrarotto (INFN - National Institute for Nuclear Physics)

padme_ferrarotto.pdf

Break: Coffee

Calibration & operation

Convener: Felix Sefkow (Deutsches Elektronen-Synchrotron (DE))

13 Calibration techniques and strategies for the present and future LHC electromagnetic calorimeters

Speaker: Martin Aleksa (CERN)

CHEF2017-EM-Calorimetry-LHC-02102017.pdf

CHEF2017-EM-Calorimetry-LHC-02102017.pptx

14 On the limits of the hadronic energy resolution of a calorimeter

In particle physics experiments, the quality of calorimetric particle detection is typically considerably worse for hadrons than
for electromagnetic showers. In this talk, I will discuss the root causes of this
problem and evaluate two different methods that have been exploited to remedy this situation: compensation and dual-readout. It turns out that the latter approach is more promising, as evidenced by theoretical considerations, Monte Carlo simulations and experimental results.

Speaker: Richard wigmans (Texas Tech)

chef17talk.pdf

15 Calibration and Performance of the ATLAS Tile Calorimeter During the LHC Run 2

The Tile Calorimeter (TileCal) is the hadronic sampling calorimeter of ATLAS experiment at the Large Hadron Collider (LHC). TileCal uses iron absorbers and scintillators as active material and it covers the central region |η| < 1.7. Jointly with the other calorimeters it is designed for measurements of hadrons, jets, tau-particles and missing transverse energy. It also assists in muon identification. TileCal is regularly monitored and calibrated by several different calibration systems:
a Cs radioactive source that illuminates the scintillating tiles directly, a laser light system to directly test the PMT response, and a charge injection system (CIS) for the front-end electronics. These calibrations systems, in conjunction with data collected during proton-proton collisions, provide extensive monitoring of the instrument and a means for equalizing the calorimeter response at each stage of the signal propagation. The performance of the calorimeter has been established with cosmic ray muons and the large sample of the proton-proton collisions. The response of high momentum isolated muons is used to study the energy response at the electromagnetic scale, isolated hadrons are used as a probe of the hadronic response. The calorimeter time resolution is studied with multijet events. A description of the different TileCal calibration systems and the results on the calorimeter performance during the LHC Run 2 will be presented.

Speaker: Leonor Cerda Alberich (Univ. of Valencia and CSIC (ES))

Tile_CHEF2017_LCerda.pdf

16 Calibration of the CMS Hadron Calorimeter in Run2

The calibration of energy scale of the CMS Hadron Calorimeter is performed using isolated charged hadrons. This approach can be applied in the areas covered by the tracking system, which allows high-precision measurement of the momenta of charged particles. The performance of the calibration procedure is discussed including the impact of pileup and the developed technique of correction for pileup. The studies of selection efficiency and isolation constraints on simulated samples are presented as well as the results of calibration using 2016 collision data. The achieved uncertainty of the response to hadrons is 3.4% in the barrel and 2.6% in the endcap region
(at $|\eta|<$2) and is dominated by the systematic uncertainty due to pileup contribution.

Speakers: Marina Chadeeva (National Research Nuclear University MEPhI (RU)), Natalia Lychkovskaya (Institute for Theoretical and Experimental Physics (RU))

chadeeva_chef2017.pdf

Social events: Welcome reception

Tuesday, 3 October

Prototypes, upgrades and concepts

Convener: Kiyotomo Kawagoe (Kyushu University (JP))

17 Digital Hadron Calorimetry

Particle Flow Algorithms (PFAs) attempt to measure each particle in a hadronic jet individually, using the component or detector subsystem providing the best energy/momentum resolution. The application of PFAs has been shown to achieve energy resolutions of 3 – 4% for hadronic jets produced in a future lepton collider. In this context the CALICE collaboration developed the Digital Hadron Calorimeter (DHCAL) which emphasizes granularity over single particle energy resolution. The large DHCAL prototype was built in 2008-2010, following the successful completion of the test beam program of a small size prototype.

The DHCAL uses Resistive Plate Chambers (RPCs) as active media and is read out with 1 x 1 cm2 pads and digital (1 - bit) resolution. A single layer of the DHCAL measures roughly 1 x 1 m2 and consists of 96 x 96 pads. In order to obtain a unique dataset of electromagnetic and hadronic interactions with unprecedented spatial resolution, the DHCAL went through a broad test beam program. The DHCAL was tested with steel and tungsten absorber structures, as well as with no absorber structure, at the Fermilab and CERN test beam facilities over several years. In addition to conventional calorimetric measurements, the DHCAL offers detailed measurements of event shapes, rigorous tests of simulation models and various tools for improved performance due to its very high spatial granularity.

Here we report on the results from the analysis of pion and positron events, including the intricate calibration procedure. Results of comparisons with the Monte Carlo simulations are also discussed. The analysis demonstrates the unique utilization of detailed event topologies and the development of software compensation tools.

Speaker: Burak Bilki (The University of Iowa (US))

CHEF17_Bilki_DHCAL_v1.pdf

18 Technical instrumentation R&D for ILD large scale device

The ILD silicon-tungsten electromagnetic calorimeter (ILD Si-W ECAL) is a sampling calorimeter with tungsten absorber and highly segmented silicon layers to achieve precise jet energy measurements by particle flow concept. While CALICE is centered on the single ECAL Active Sensor Unit (ASU) prototype and its tests, specific R&D is going on larger scale detector approaching the size of an ILD slab. In particular, it addresses the questions of proper clock and power distribution along the long slab, interconnections between the individual ASUs, DAQ electronics bandwidth, mechanical aspects of slab assembly and its scalability for industrial mass production. We also think about the calibration of the large detectors. With cosmics one can reach a few percent absolute calibration per pixel in one day. A few percent non-linearity for low MIP-like signals and the non-linearity beyond the dynamic range could be measured with the charge injection.

Speaker: Vladislav Balagura (Centre National de la Recherche Scientifique (FR))

ILD_long_slab_balagura.pdf

19 The Semi-Digital Hadronic Calorimeter (SDHCAL) prototype

The successful running of the technological prototype of the Semi-Digital Hadronic CALorimter (SDHCAL) proposed to equip the future ILD detector of the ILC has provided excellent results in terms of energy linearity and resolution and also tracking capabilities. Stability with time of the prototype is also successfully tested.

To validate completely the SDHCAL option for ILD, a new R&D activities have started. The aim of such activities is to demonstrate the ability to build large detectors (> 2m2). The construction of efficient detectors of such a size necessitates additional efforts to ensure the homogeneity and the efficiency of these large detectors.

Another important point of the new activities is to use a new version of the HARDROC ASIC that was used in the prototype with success. The new version has several advantages with respect to the one used in the SDHCAL prototype such as the zero suppression and the I2C protocol.

Another development is the DAQ electronic board. A new one is proposed. In addition to a reduced size to cope with the ILD requirements, new features are being implemented. A TCP/IP protocol is adopted in the new card to ensure the coherency of the data transmission. The TTC protocol is also to be used to distribute the clock to the different ASIC on the electronic board. The new DAQ board is being conceived to have the capability to address up to 432 ASICs of 64 channels each.

600 new HARDROC has been already produced and tested, and the electronic boards are being produced now. In addition, some new few DAQ boards are now under tests.

A new cassette, to host the active layer while being as before a part of the absorber, is being also conceived. The challenge is to maintain a good rigidity to ensure the perfect contact between the electronic board and the GRPC and also to facilitate the dissipation of the ASIC heating.

Finally, the mechanical structure of the new prototype will use a new welding technique to reduce the dead zones and provide less deformed structure. Few attempts using the electron beam welding technique to build small setup have been realized at CERN.

Speaker: Maria Fouz Iglesias (Centro de Investigaciones Energéti cas Medioambientales y Tecno)

SDHCAL_CHEF2017_sp2.pdf

20 Upgrade of the ATLAS hadronic Tile Calorimeter for the High luminosity LHC

The Tile Calorimeter is the hadronic calorimeter covering the central region of the ATLAS detector at the Large Hadron Collider. It is a scintillator-steel sampling calorimeter read out via wavelength shifting fibers coupled to photomultiplier tubes (PMT). The PMT signals are digitized and stored on detector until a trigger is received. The High-Luminosity phase of LHC (HL-LHC)expected to begin in year 2026 requires new electronics to meet the requirements of a 1 MHz trigger, higher ambient radiation, and for better performance under higher pileup. All the TileCal on- and off-detector electronics will be replaced during the shutdown of 2024-2025. PMT signals from every TileCal cell will be digitized and sent directly to the back-end electronics, where the signals are reconstructed, stored, and sent to the first level of trigger at a rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Changes to the electronics will also contribute to the data integrity and reliability of the system.
Three different front-end options are presently being investigated and will be chosen after studies of simulated physics performance and evaluation of prototype performance in test beams. A hybrid demonstrator compatible with the current ATLAS detector has been developed. The demonstrator is undergoing extensive testing and is planned for future insertion in ATLAS.

Speaker: Sergi Rodriguez Bosca (Univ. of Valencia and CSIC (ES))

SergiRodriguez_chef2017.pdf

21 Upgrade of the LHCb Calorimeter system

In 2019-2020, the LHCb collaboration will enter into the Phase I upgrade. The goal is to increase the working luminosity up to 2·1033 cm-2s-1. To achieve this, the hardware based Level 0 trigger will be replaced by a full software trigger. All the events will be read out; the event reconstruction and selection will be done in real time at a large CPU farm.

In the first part of the talk, the LHCb Calorimeter system Phase I upgrade will be described. The main modifications will consist in removal of the Preshower subdetector assembly and full replacement of the frontend electronics of ECAL and HCAL.

The second part of the talk will be devoted to the future Phase II upgrade, which is now being developed by the LHCb Collaboration. The Phase II Upgrade is supposed to make LHCb able to work at even higher luminosity, 2·1034 cm-2s-1. This implies essential revision of the Calorimeter system. The options for the Phase II LHCb Calorimeter upgrade will be discussed.

Speaker: Iouri Guz (Institute for High Energy Physics (RU))

Guz_CHEF2017_LHCbCaloUpgrade.pdf

Guz_CHEF2017_LHCbCaloUpgrade.pptx

Break: Coffee

Prototypes, upgrades and concepts

Convener: Richard wigmans (Texas Tech)

22 A HGTD for the Phase-II upgrade of the ATLAS Calorimeter system: detector concept description and first beam test results

The expected increase of the particle flux at the high luminosity phase of the LHC (HL-LHC) with instantaneous luminosities up to L ≃ 7.5 × 1034 cm−2 s-1 will have a severe impact on the ATLAS detector performance. The pile-up is expected to increase on average to 200 interactions per bunch crossing. The reconstruction and trigger performance for electrons, photons as well as jets and transverse missing energy will be severely degraded in the end-cap and forward region, where the liquid Argon based electromagnetic calorimeter has coarser granularity compared to the central region. A High Granularity Timing Detector (HGTD) is proposed in front of the liquid Argon end-cap calorimeters for pile-up mitigation at Level-0 (L0) trigger level and in the offline reconstruction.

This device should cover the pseudo-rapidity range of 2.4 to about 4.2. Four layers of Silicon sensors are foreseen to provide a precision timing information for minimum ionizing particle with a time resolution better than 50 pico-seconds per readout cell in order to assign the particle to the correct vertex. Each readout cell has a transverse size of 1.3 mm × 1.3 mm leading to a highly granular detector with more than 6 millions of readout electronics channels. Low Gain Avalanche Detectors (LGAD) technology has been chosen as it provides an internal gain good enough to reach large signal over noise ratio needed for excellent time resolution.

The requirements and overall specifications of the High Granular Timing Detector at the HL-LHC will be presented as well as the conceptual design of its mechanics and electronics. Beam test results and measurements of irradiated LGAD silicon sensors, such as gain and timing resolution, will be shown.

Speaker: Didier Lacour (LPNHE-Paris CNRS/IN2P3)

CHEF2017-HGTD-lacour-041017VF.pdf

23 The CMS HGCAL detector for HL-LHC upgrade

The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry, and hallmarks the issue for future colliders. As part of its HL-LHC upgrade program, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The ECAL and a large fraction of HCAL will be based on hexagonal silicon sensors of 0.5 - 1 cm2 cell size, with the remainder of the HCAL based on highly-segmented scintillators with SiPM readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection. An overview of the HGCAL project is presented, covering motivation, engineering design, readout and trigger concepts, and performance (simulated and from beam tests).

Speaker: Jean-Baptiste Sauvan (Centre National de la Recherche Scientifique (FR))

171003_CHEF_sauvan_HGCal_v4.pdf

24 Prototype tests for a highly granular scintillator-based hadron calorimeter

Within the CALICE collaboration, several concepts for the hadronic calorimeter of a future linear collider detector are studied. After having demonstrated the capabilities of the measurement methods in "physics prototypes", the focus now lies on improving their implementation in "engineering prototypes", that are scalable to the full linear collider detector. The Analog Hadron Calorimeter (AHCAL) concept is a sampling calorimeter of tungsten or steel absorber plates and plastic scintillator tiles read out by silicon photomultipliers (SiPMs) as active material. The front-end chips are integrated into the active layers of the calorimeter and are designed for minimal power consumption (power pulsing). The versatile electronics allows the prototype to be equipped with different types of scintillator tiles and SiPMs. A large prototype for beam tests with hadronic showers with ~24000 channels, corresponding to ~4.3 I, is under construction. As a first step, the absorber stack was partly equipped with several types of scintillator tiles and SiPMs and exposed to electron, muon and hadron beams. This also allowed to study system and integration aspects. The experience of these beam tests as well as the availability of new generation SiPMs with much reduced noise and better device-to-device uniformity resulted in an improved detector design with surface-mount SiPMs allowing for easier mass assembly. A small setup, based on the improved design, with ~17 X0 (~1.8 I) thickness has been built and tested with and without magnetic field in muon and electron beams. The presentation will discuss the testbeam measurements, the improved detector design and the ongoing construction of the large prototype.

Speaker: Felix Sefkow (Deutsches Elektronen-Synchrotron (DE))

CALICE-AHCAL-CHEF17-FS.pdf

25 Progress of CEPC scintillator-tungsten structure ECAL

The circular electron and positron collider (CEPC) was proposed as a future Higgs factory. To meet the physics requirements, a particle flow algorithm-oriented calorimeter system with high energy resolution and precise reconstruction is considered. A sampling calorimeter with scintillator-tungsten structure is selected as one of the electromagnetic calorimeter (ECAL) options due to its good performance and relatively low cost. We present the design, the test and the optimization of the scintillator module read out by silicon photomultiplier (SiPM), including the design and the development of the electronics. To estimate the performance of the scintillator and SiPM module for particles with different momentum, the beam test of a mini detector prototype without tungsten shower material was carried out at the E3 beams in Institute of High Energy Physics (IHEP). The results are consistent with the ones from the simulation. These studies provide a reference and promote the development of particle flow electromagnetic calorimeter for the CEPC.

Speaker: Mingyi Dong (Institute of High Energy Physics, Chinese Academy of Sciences)

Progress of CEPC scintillator-tungsten structure ECAL.pdf

Break: Lunch

test beam results & analysis

Convener: Laurent Serin (LAL-CNRS/IN2P3 Orsay(Fr))

26 Dual-Readout Calorimetry: recent results from RD52 and plans for experiments at future e+e- colliders

The Dual-Readout calorimetry, developed to overcome the main limiting factor in hadronic energy measurements, has been thoroughly investigated by the DREAM/RD52 collaboration during the last 15 years. The latest results show that very interesting performance may be obtained for both e.m. and hadronic showers, together with excellent standalone e/π separation. These results and the plans (and the expected performance) for dual-readout calorimetry in the CepC/FCC-ee environment, will be presented and discussed.

Speaker: Roberto Ferrari (INFN Pavia (IT))

chef17_rf.pdf

27 test beam results with an ultra thin LumiCal detector planes

The luminosity of the Future Linear Colliders will be measured  by counting Bhabha scattering events at low angles coincident in the two calorimeters (LumiCal) located symmetrically at opposite sides of the interaction point. The LumiCal has been designed as a 30 layers sampling calorimeter with tungsten as absorbel and silicon sensors. Each silicon layer composed of 12 tails with 256 pads. In order to have a calorimeter with small Moliere radius, the distance between two tungsten planes should be minimized.
During the two last years, an extensive study of different technologies allowed to reach detector layers of 0.7 mm thickness, equipped in order to read all pads. In summer 2016, a fully equipped prototype with a  two layer tracker and a six layers calorimeter was tested at DESY.
 The aim of the tracker, installed in front of the Luminal, is to distinguish electrons from photons (electron tagger). Shower development (longitudinal and radial) and tracker results will be presented.

Speaker: Oleksandr Borysov (Tel Aviv University (IL))

lumical_tb_chef17.pdf

28 Energy Reconstruction of Hadrons in highly granular combined ECAL and HCAL systems

The CALICE collaboration develops highly granular calorimeters for present and future collider experiments. Among the physics prototypes already tested extensively in particle beams are Silicon-Tungsten (SiW ECAL) and Scintillator-Tungsten (Sc ECAL) electromagnetic calorimeters and a scintillator – SiPM based analog hadron calorimeter (AHCAL). These prototypes were operated together in hadron beams, permitting the study of the performance in combined ECAL / HCAL systems.

This contribution will discuss the energy reconstruction and calibration for the SiW ECAL + AHCAL and Sc ECAL + AHCAL configuration , which has to account for the differing geometry and, in the first case, for the different readout technology in the sub-systems. Two techniques for the energy reconstruction are used, a standard reconstruction based on calibrated sub-detector energy sums, and one based on a software compensation algorithm making use of the local energy density information provided by the high granularity. The software compensation-based algorithm improves the hadronic energy resolution by up to 30% compared to the standard reconstruction. The energy resolution in the combined system is comparable to the one achieved for showers starting only in the AHCAL, demonstrating the success of the inter-calibration of the different subsystems.

Speakers: Yasmine Israeli, Yasmine Israeli (Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D)

CHEF_talk.pdf

29 Latest R&D news and beam test performance of the highly granular SiW-ECAL technological prototype for the ILC

High precision physics at future colliders require unprecedented high precision calorimeters. The needed precision is achieved thanks to the Particle Flow Algorithm (PFA) and highly granular calorimeters. The physical proof of concept was performed in the prvious campaign of beam tests of physic prototypes within the CALICE collaboration. We present here the latest beam and laboratory test results and R&D developments for the Silicon-Tungsten Electromagnetic Calorimeter technological prototype with fully embedded very front-end (VFE) electronics for the International Large Detector at the International Linear Collider future project.
Special emphasis will be done in presentation and discussion of the results coming from the beam test done at DESY in June 2017. The physics planning for such beam test consisted in the calibration and commissioning of the current set of available SiW ECAL modules; the commissioning and test of the new DAQ and DQM developments; and the test of performance of individual slabs under 1T magnetic fields.

Speaker: Adrian Irles (LAL)

Irles_CHEF_2.pdf

30 Detailed measurements of shower properties in a high granularity digital electromagnetic calorimeter

Increasing precision requirements on particle reconstruction in future collider experiments ask for calorimeter systems with a high granularity. These calorimeters offer a unique and detailed view into electromagnetic and hadronic particle showers. We have performed test measurements with a digital Si-W electromagnetic calorimeter prototype using high granularity Monolithic Active Pixel Sensors. The individual readout of the 24 sensor layers and the granularity of 30×30 µm2 allow measurement of showers in unprecedented detail.
Measured average shower distributions in 3 dimensions for electrons with beam energies between 2 and 244 GeV are presented. The lateral distributions per layer are unique measurements with this detector. These have been compared to different analytical functions. Because none of the earlier proposed functions provide a perfect description, a new parameterisation has been introduced, which provides a better fit.
Detailed shower measurements are a perfect tool for testing and improving shower simulation models. We compare the measured shower distributions to MC simulations with GEANT4. While the overall features are in good agreement, a number of deviations are observed which will be pointed out and discussed.
In addition, we will present first studies of event-by-event fluctuations of the shower development in our detector, such as the distributions of shower start position, shower depth and width in data and MC events.

Speaker: Naomi Van Der Kolk (Max-Planck-Institut fur Physik (DE))

CHEF_FoCal_NvanderKolk.pdf

Break: Coffee

Prototypes, upgrades and concepts

Convener: Frank Simon (Max-Planck-Institut fuer Physik)

31 CALICE scintillator ECAL base unit

CALICE scintillator ECAL module which consists of a scintillator strip layer and an embedded electronics layer will be reported. In total 144 scintillator strips whose dimentions (5mmx45mmx2mm thick) are covering 18cm x 18cm surface, where the same size ECAL base unit called EBU, is located behind the strip layer equipping 144 photo-sensors and front end read out system. The amplifier, shaper, ADC and voltage controller are integrated into four ASICs (SPIROC2b). The performance with 10um pitch MPPC and a few different scintillator materials are compared and reported here. Smallness of sensitive area of photo sensor makes difficult to have valuable data on the system. We will discuss the problem and solutions.

Speakers: Toru Takeshita (Shinshu University (JP)), Toru Takeshita (Shinshu University (JP))

CALICE EBU-CHEF2017.pdf

32 High granularity digital Si-W electromagnetic calorimeter for forward direct photon measurements at LHC

It is widely expected that the non-linear growth of parton densities at low x predicted from linear QCD evolution will lead to gluon saturation. As a decisive probe of gluon saturation, the measurement of forward (3.5 < y < 5) direct photons in a new region of low x (10-5 - 10-6) in proton-nucleus collisions at the LHC is proposed. An extremely high-granularity electromagnetic calorimeter is proposed as a detector upgrade to the ALICE experiment. This Forward Calorimeter (FoCal) is required to discriminate direct photons from decay photons with very small opening angles from neutral pions.
To facilitate the design of the upgrade and to perform generic R&D necessary for such a novel calorimeter, a compact digital Si-W sampling electromagnetic calorimeter prototype, using Monolithic Active Pixel Sensors (MAPS) with a granularity of 30×30 µm2 and a total length of 28 X0 has been built and tested with beams. The prototype features ~39 million pixels and an extremely small Molière radius ~11mm.

We will present the design principle of the proposed FoCal detector, and the realisation of the prototype. Test beam results will be discussed, which show good energy linearity and resolution. These results show the successful proof of principle of particle counting calorimetry technology. This technology has an excellent position resolution for electromagnetic showers (< 30µm) and should allow the separation of two photon showers down to distances of a few mm. In addition, it should provide unprecedented capabilities for applications of particle flow algorithms in future calorimeters.

Speaker: Thomas Peitzmann (Nikhef National institute for subatomic physics (NL))

chef-focal-tp.key

chef-focal-tp.pdf

33 Design of an electro-magnetic calorimeter for the SHiP experiment with shower direction reconstruction capability

A status report about the options considered for the electromagnetic calorimeter for the Hidden
Sector Detector of the SHiP experiment will be presented. A “cheap” sampling calorimeter is under
design with an unusual requirement that it be able, standalone, to reconstruct the vertex and
momentum of an unknown particle decaying into final states with only 2 or more photons, produced
between 5 and 60 m upstream of the calorimeter.

Speaker: Dr Walter Marcello Bonivento (INFN Cagliari)

Lyon_CHEF.pdf

34 HCAL progress related to CEPC

This talk introduce the progress of hadron calorimeter (HCAL) related to Circular Electron Positron Collider (CEPC). Three sensitive detector such as plastic scintillator， RPC detector and GEM/THGEM detector was tried to be applied on CEPC hadron calorimeter. Some progress has been made, and some results have been published.

Speaker: Boxiang Yu

The progress of CEPC-HCAL.pdf

35 Online track detection in triggerless mode for INO

The India based Neutrino Observatory (INO) is a proposed particle physics research project to study atmospheric neutrinos[ CITATION INO06 \l 16393 ]. INO – Iron Calorimeter (ICAL) will consist of 28,800 detectors having 3.6 million electronic channels expected to activate with 100 Hz singles rate producing data at the rate of 3GBps. Data collected contains a few real hits generated by muon track and the remaining noise induced spurious hits. Estimated reduction factor after filtering out data of interest from generated data is of the order of 103. This makes trigger generation critical for efficient data collection and storage. Trigger is generated by detecting coincidence across multiple channels satisfying trigger criteria[ CITATION Das12 \l 16393 ], within a small window of 200ns in the trigger region. As the probability of neutrino interaction is very less, track detection algorithm has to be efficient and fast enough to process 5 * 106 events/sec without introducing significant dead time so that not even a single neutrino event is missed out.
A hardware based trigger system is presently proposed for on-line track detection considering stringent timing requirements. Though the trigger system can be designed with scalability, a lot of hardware and interconnections make it a complex and expensive solution. Also its flexibility is limited. A software based track detection approach working on the hit information offers an elegant solution with possibility of varying trigger criteria for selecting various potentially interesting physics events. An event selection approach for an alternative triggerless readout scheme has been developed. The algorithm is mathematically simple, robust and parallelizable. It has been validated by detecting simulated events for energies of the primary neutrinos of the range of 1 GeV – 10 GeV with 100% efficiency at a processing rate of 60μs/event on a 16 core machine. The algorithm and result of a proof-of-concept for its faster implementation over multiple cores is presented. The paper also discusses about harnessing the compute capabilities of multi-core computing farm, thereby requiring only optimum number of nodes for the proposed system.
*Corresponding author.
E-mail address: anushri@barc.gov.in (Anushri J.).
References:
[1]
“INO Project Report,” in http://www.ino.tifr.res.in/ino/, 2006.
[2]
S. Dasgupta, N. K. Mondal, D. Samuel, M. N. Saraf, B. Satyanarayana and S. S. Upadhya, “Development of trigger scheme for the ICAL detector of India-based Neutrino Observatory,” Nuclear Instruments and Methods in Physics Research A, pp. 105-113, 2012.

Speaker: Anushri Jain

CHEF2017_Talk_AnushriJain.pdf

CHEF2017_Talk_AnushriJain.pptx

36 Study of the Electromagnetic Calorimeter for Multi Purpose Detector (MPD) on the collider NICA

In design of barrel ECal for collider experiment with non-projective geometry of its modules there are some unpleasant feature such as increase of number of hits at large angles of incidence of the particles coming from beam interaction point.
Part of the hits are separated from main shower and thus are not included in the total energy deposition. This leads to reduction of the total energy of hits collected in the cluster. With increasing the particle incidence angle the reconstruction energy decreased. We propose the projective geometry of the shashlik type of modules for barrel ECal of the Multi Purpose Detector (MPD) on the collider of heavy ions NICA.

Speaker: Igor Tyapkin (JINR Dubna)

ecal_mpd_chef2017_IT.pdf

Wednesday, 4 October

Trigger, HV, electronics

Convener: Vincent Boudry (LLR - Ecole Polytechnique/CNRS-IN2P3)

37 Front-End Electronics for Imaging/timing Calorimetry

Speaker: Christophe De La Taille

CdLT_CHEF_4oct17.pdf

38 The front-end data conversion and readout electronics for the CMS ECAL upgrade

The High Luminosity LHC (HL-LHC) will require a significant upgrade of the readout electronics for the CMS Electromagnetic Calorimeter (ECAL). The Very Front-End (VFE) output signal will be sampled at 160 MS/s (i.e. four times the current sampling rate) with a 13 bits resolution. Therefore, a high-speed, high-resolution ADC is required. Moreover, each readout channel will produce 2.08 Gb/s, thus requiring a fast data transmission circuitry.
A new readout architecture, based on two 12 bit, 160 MS/s ADCs, lossless data compression algorithms and fast serial links has been developed for the ECAL upgrade. These functions will be integrated in a single ASIC which is currently under design in a commercial CMOS 65 nm technology using radiation damage mitigation techniques.

Speaker: Gianni Mazza (Universita e INFN Torino (IT))

CHEF2017_Presentation-GMazza.pdf

39 The Phase-2 electronics upgrade of ATLAS LAr Calorimeter

The LHC high-luminosity upgrade in 2024-2026 requires the associated detectors to operate at luminosities about 5-7 times larger than assumed in their original design. The pile-up is expected to increase to up to 200 events per proton bunch-crossing.
The current readout of the ATLAS Liquid Argon (LAr) Calorimeters does not provide sufficient buffering and bandwidth capabilities to accommodate the hardware triggers requirements imposed by these harsh conditions. Furthermore, the expected total radiation doses are beyond the qualification range of the current front-end electronics. For these reasons an almost complete replacement of the LAr front-end and back-end readout system is foreseen for the 182,500 readout channels.

The system will follow a free-running architecture, where the calorimeter signals are amplified, shaped and digitized by on-detector electronics, then sent at 40MHz to the backend, which performs the energy and time reconstruction, send inputs to the trigger, and buffers the data until trigger signals are received.
The triangular calorimeter signals need to be amplified and shaped over a dynamic range of 16 bits, with low noise and excellent linearity. Developments of low-power preamplifiers and shapers to accommodate these requirements are ongoing in two technologies. In CMOS 65 nm, a fully differential design with a programmable termination, two gains and a shaper stage with programmable peaking time is being studied. A second design uses 130 nm CMOS, and features a new line termination preamplifier using an electronically cooled resistance.
In order to digitize the analogue signals on two gains after shaping, radiation-hard, low-power 40 MHz 14-bit ADCs are being developed using a SAR architecture in 65 nm CMOS technology. This architecture will lead to a total bandwidth of 275 Tbps to be sent off-detector. A newly designed VCSEL array driver shows that the required 10Gb/s transfer rate at 20-35mW per channel is achieved, suitable for integration into a low-power optical link package.

Results from the design studies on the performance of the components of the LAr readout system will be presented, as well as the results of the tests of the first prototypes.

Speaker: Brigitte Vachon (McGill University, (CA))

Vachon.pdf

40 Electronics and triggering challenges for the CMS High Granularity Calorimeter

The High Granularity Calorimeter (HGCAL), presently being designed by the CMS collaboration to replace the CMS endcap calorimeters for the High Luminosity phase of LHC, will feature six million channels distributed over 52 longitudinal layers. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0-10 pC), low noise (~2000e- to be able to calibrate on single minimum ionising particles throughout the detector lifetime) and low power consumption (~10mW/channel), as well as the need to select and transmit trigger information with a high granularity. Exploiting the intrinsic precision-timing capabilities of silicon sensors also requires careful design of the front-end electronics as well as the whole system, particularly clock distribution. The harsh radiation environment and requirement to keep the whole detector as dense as possible will require novel solutions to the on-detector electronics layout. Processing all the data from the HGCAL imposes equally large challenges on the off-detector electronics, both for the hardware and incorporated algorithms. We present an overview of the complete electronics architecture, as well as the performance of prototype components and algorithms.

Speaker: Artur Lobanov (LLR – Ecole Polytechnique (FR))

ALobanov_HGCAL_CHEF2017.pdf

41 Performance study of SKIROC2/A ASIC for ILD Si-W ECAL

The International Large Detector (ILD) is one of two detector concepts of International Linear Collider (ILC). The ILD silicon-tungsten electromagnetic calorimeter (ILD Si-W ECAL) is a sampling calorimeter with tungsten absorber and highly segmented silicon layers to achieve precise jet energy measurements by particle flow concept. Readout ASICs should be embedded between absorber and detector layers.
SKIROC2 is the ASIC for the ILD SiW-ECAL, developed by IN2P3/Omega group. It consists of 64 input channels, preamplifier and two gain slow shapers, a fast shaper for triggering, 15 analog memory cells to accumulate multiple events with up to 2625 bunches colliding in a beam train. It has 12-bit ADC and TDC outputs, multiplexed and sent via a daisy-chained digital bus line. One of the specific characteristics of the ASIC is the power-pulsing capability, to switch off unnecessary part (for example, amplifiers are only powered at acquisition stage) to reduce the power consumption and dissipation.
We produced prototype sensor layers equipped with SKIROC2 and conducted test beams since 2012. We found several issues related either ASIC or PCB. For example, we suffered from multiple fake triggering occurred just after the right trigger (which we called retriggering), which improves at the second prototype at 2014 but still exists. To investigate the issues, we prepared dedicated ASIC evaluation boards with either BGA sockets or directly soldered SKIROC2. The evaluation boards have an analog probe to check the amplifier outputs, and investigate various features of SKIROC2 including TDC, external triggers and so on.
We will report the performance study with the evaluation boards, including signal-to-noise ratio, TDC performance, and investigating the retriggering issues. We also present the comparison of performance with the prototype on the test beam. In addition, the new ASIC, SKIROC2A, has been prepared recently with improved features such as more dynamic range for individual trigger threshold control and TDC dead time. The comparison of features and performance between SKIROC2 and SKIROC2A with the evaluation board is presented as well.

Speakers: Taikan Suehara (Kyushu University (JP)), Taikan Suehara (Kyushu University)

171004-chef2017-suehara-sk2.pdf

Break: Coffee

Trigger, HV, electronics

Convener: Christophe De La Taille

42 High precision, low disturbance calibration of the High Voltage system of the CMS Barrel Electromagnetic Calorimeter

The CMS Electromagnetic Calorimeter utilizes scintillating lead tungstate crystals, with avalanche photodiodes (APD) as photodetectors in the barrel part. The high voltage system, consisting of 1224 channels, biases groups of 50 APD pairs, each at a voltage of about 380 V. The sensitivity of the APD gain to the bias voltage is 3%/V. A stability of better than 60 mV is therefore required to have a negligible impact on the calorimeter energy resolution. Until 2015, manual calibrations were performed once per year during LHC year-end technical stops. A new, less labour-intensive, calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision and permits more frequent checking of the APD bias voltages during the year. The system is discussed in detail and the first operational experience in CMS is presented.

Speaker: Simone Gelli (Sapienza Universita e INFN, Roma I (IT))

CHEF2017_HV_SimoneGelli.pdf

43 The CMS Level-1 Trigger system for the LHC Run II

During the second run of operation, the LHC delivers proton-proton collisions at a
centre-of-mass energy of 13 TeV with a peak instantaneous luminosity of $1.5 \cdot 10^{34} cm^{-2}s^{-1}$ in 2016, almost double the peak luminosity reached during
Run-1 and far larger than the design value. To maintain acceptance for proton and
heavy ion collision events of interest without exceeding the 100 kHz limit, the CMS
Level-1 (L1) trigger has been being upgraded. The upgraded system makes use of
new Xilinx Virtex-7 based AMC cards form the microTCA technology. The L1
calorimeter trigger, which finds electrons, photons, tau leptons, jet candidates and
computes energy sums has been upgraded implementing isolation requirement,
multivariate regression, and pile-up mitigation techniques in order to reach
acceptable performance. The CMS muon detector was designed for preserving the
complementarity and redundancy of three separate muon detection systems,
Cathode Strip Chambers (CSC), Drift Tubes (DT) and Resistive Plate Chambers
(RPC), until they were combined at the input to the Global Trigger. The upgrade of
the muon trigger aimed at exploiting the redundancy of the three muon detection
systems earlier in the trigger processing chain in order to obtain a high-performance
trigger with higher efficiency and better rate reduction, implementing pattern
recognition and MVA (Boosted Decision Tree) regression techniques directly in the
trigger boards. In addition, the new global trigger is capable of evaluating complex
selection algorithms such as those involving the invariant mass of trigger objects.
The talk will cover the technological aspects of the Run II calorimeter trigger system.
Results of its performance during the 2016 collisions of the LHC will be presented
along with 2017 optimization for more intense conditions foreseen.

Speaker: Alex Tapper (Imperial College (GB))

chef2017.pdf

44 The NA62 Liquid Krypton calorimeter Level-0 trigger and readout electronics

The NA62 experiment at CERN SPS accelerator studies the ultra-rare decays of charged kaons. The high-resolution Liquid Krypton (LKr) electromagnetic calorimeter is a key component of the experiment photon-veto system. The LKr readout system comprises 14 thousand 14-bit ADC acquisition channels, 432×1 Gbit Ethernet data request and readout links routed to the experiment computer farm. The calorimeter Level-0 trigger is a parallel system composed of 37 boards, carrying 111 Input/Output mezzanines and 221 FPGAs devices. In this contribution we present the architecture, operation and performances of the system during the 2017 data taking.

Speaker: Nico De Simone (INFN e Universita Roma Tor Vergata (IT))

desimone-chef2017.pdf

45 ATLAS LAr Calorimeter Trigger Electronics Phase-1 Upgrade

The upgrade of the Large Hadron Collider (LHC) scheduled for a shut-down period of 2019-2020, referred to as the Phase-I upgrade, will increase the instantaneous luminosity to about three times the design value. Since the current ATLAS trigger system does not allow sufficient increase of the trigger rate, an improvement of the trigger system is required. The Liquid Argon (LAr) Calorimeter read-out will therefore be modified to use digital trigger signals with a higher spatial granularity in order to improve the identification efficiencies of electrons, photons, tau, jets and missing energy, at high background rejection rates at the Level-1 trigger. The new trigger signals will be arranged in 34000 so-called Super Cells which achieves 5-10 times better granularity than the trigger towers currently used and allows an improved background rejection.
The readout of the trigger signals will process the signal of the Super Cells at every LHC bunch-crossing at 12-bit precision and a frequency of 40 MHz. The data will be transmitted to the back-end at 5.12 Gb/s using a custom serializer and optical converter. ASICs have been developed for ADC, serializer and transmitter for this project and PCB boards are being developed now. In the new back-end system, the received digital data will be processed with a FIR filter, optimal filtering, on a FPGA (Intel-FPGA Arria-X) to identify the bunch crossing and extract the transverse energy with a fixed latency. The results of the digital processing are transferred to the level-1 trigger system for trigger object reconstruction. The backend system is developed using the ATCA architecture. ATCA carrier blade with RTM will carries four Advanced Mezzanine Cards with the FPGA. In total, the backend system will consist from 31 carrier boards in three ATCA shelfs.
In order to verify the full functionality of the new Liquid Argon trigger readout system, a demonstrator set-up has been installed on the ATLAS detector and has been operated in parallel to the regular ATLAS data taking during the LHC Run-2. We have collected data with 13 TeV proton-proton collisions during the LHC Run-2, and have observed real pulse from the detector through the demonstrator system.
The talk will give an overview of the Phase-I Upgrade of the ATLAS Liquid Argon Calorimeter readout and present the custom developed hardware including their role in real-time data processing and fast data transfer. This contribution will include the performance of the newly developed ASICs including their radiation tolerance and quality assurance, the performance of the prototype boards in the demonstrator system. Results of the system integration test with the final prototypes will be reported.

Speaker: Georges Aad (CPPM, Aix-Marseille Université, CNRS/IN2P3 (FR))

CHEF2017.pdf

Break: Lunch

Social events: Excursion

Social events: Banquet

Thursday, 5 October

Prototypes, upgrades and concepts

Convener: Katja Krueger (Deutsches Elektronen-Synchrotron (DE))

46 ECAL device in view of the ILC staging proposal

In view of the LHC results, in order to mitigate the cost of an ILC or at least to spread
it in time, the prospect of a staged development for ILC takes consistence.
An initial phase at an energy of about 250 GeV is strongly considered with a hope to go
to 380 GeV or even 500. A rather long stay at low energy suggests to revisit the detector
design for an optimisation which weighs more this phase. If the particle flow approach
keeps all its virtues the balance between particle separation and intrinsic resolution
may shift. The reduction of the particle and jet energies may also suggest reducing field
and size. The impact of these considerations on the design of the ILD calorimeter and
specially the electromagnetic part will be examined. Proposal of timing measurement
will also be discussed.

Speaker: Jean-Claude Brient (Centre National de la Recherche Scientifique (FR))

TALK at CHEF.pdf

TALK at CHEF.pdf

TALK at CHEF.pdf

TALK at CHEF.pdf

TALK at CHEF.pptx

47 Design and performance of an electromagnetic calorimeter for a FCC-hh experiment

The physics reach and feasibility of the hadron-hadron Future Circular Collider (FCC-hh) with a centre of mass energies up to 100 TeV and unprecedented luminosities is currently under investigation. We will present the current baseline technologies for the calorimeter system of the FCC-hh reference detector: a liquid argon (LAr) electromagnetic and a scintillator-steel (Tile) hadronic calorimeter. Alternative technologies which are currently under consideration will be briefly discussed. This talk will focus on the electromagnetic calorimeter (ECAL) where requirements and feasibility will be discussed. The ECAL subdetector will have to meet the requirements on the high radiation hardness and must be able to deal with a very high number of collisions per bunch crossings (pile-up). Moreover, very good energy and angular resolution for a wide range of electrons' and photons' momentum is needed in order to meet the demands based on the physics benchmarks. First results of the performance studies with the new LAr calorimeter design will be shown.

Speaker: Anna Zaborowska (Warsaw University of Technology (PL))

FCChh_EMcalorimeter_Zaborowska.pdf

48 Design and performance studies of a hadronic calorimeter for a FCC-hh experiment

The hadron-hadron Future Circular Collider (FCC-hh) project studies the physics reach of a proton-proton machine with centre of mass energies up to 100 TeV and five times greater luminosities than at the High-Luminosity LHC. The new energy regime of the FCC-hh opens the opportunity for the discovery of physics beyond the standard model. At 100 TeV a large fraction of the W, Z, H bosons and top quarks are produced with a significant boost. It implies an efficient reconstruction of very high energetic objects decaying hadronically and producing high $p_{T}$ jets in the detector. The reconstruction of those boosted objects sets the calorimeter performance requirements in terms of energy resolution, containment of highly energetic hadron showers, and high transversal granularity. We will present the current baseline technologies for the calorimeter system of the FCC-hh reference detector: a liquid argon (LAr) electromagnetic and a scintillator-steel (Tile) hadronic calorimeter. The talk will focus on the performance studies for hadrons, in terms of single particle and jet reconstruction. We will present the achieved energy resolutions and dependences on the sampling fraction and granularity. In addition, the design considerations will be discussed.

Speaker: Jana Faltova (CERN)

hadronic_calorimeter_chef2017.pdf

49 Development of sampling calorimeter with segmented lead glass absorber

Sampling calorimeter is indispensable for physics measurement at col-
lider experiment with PFA. Uncertainty of deposit energy at absorber layer
degrade energy resolution. This problem will be solved by using lead glass as
absorber, which is clear and heavy. High energy particles produce Cherenkov
lights whose light yield corresponds to the track length in the lead glass.
This information from the absorber will improve the energy resolution of
the calorimeter. Performance of this calorimeter prototype tested for elec-
trons at ELPH beam at Tohoku University will be presented. We will discuss
the problems and its capabilities.

Speaker: Reima Terada (S)

2017CHEF-terada_v5_7.pdf

50 Large-area gas-avalanche Resistive-Plate WELL detectors: potential sampling elements for digital hadron calorimetry

Future digital and semi-digital hadron calorimeters, will consist of 40-50 layers of thin
sampling elements interposed between absorber planes. The total area coverage of such
elements could reach a few thousands of square meters, thus requiring robust, cost-
effective solutions. The thin, single-element Resistive Plate WELL (RPWELL) detector
concept could be an effective solution for DHCAL, SDHCAL and for other applications
requiring particle tracking at moderate, sub-mm spatial resolutions.
The RPWELL comprises of a single-sided Thick Gas Electron Multiplier (THGEM)
electrode, coupled to a segmented readout anode through a resistive plate (~10 9 -10 11
Ωcm). The properties of the RPWELL have been demonstrated, on series of small- and
medium-size prototypes, with Semitron ESD225 plastic or doped silicate glass resistive
plates. Beam tests with relativistic muons and pions of a 300x300 mm 2 RPWELL
detector prototype, with SRS-APV25 readout electronics were recently carried out; they
have demonstrated its potential applicability to DHCAL & SDHCAL: high detection
efficiency at low average pad multiplicity, under discharge-free operation, in both neon
and argon-based gas mixtures. Argon based mixtures are economic and allow reducing
the drift gap and hence the design of few-millimeter thick detectors.
On the basis of the knowledge accumulated, a thin, self-supporting 500x500 mm 2 glass-
RPWELL detector prototype with anode-strips readout was designed and built for the
first time; it was assembled using a gluing technique under vacuum, with the resistive
plate coupled to the anode through a resistive-layer/epoxy film.
This large-area detector prototype, with SRS/APV25 electronics, yielded good
performance at the laboratory. It will undergo extensive test-beam investigations in July
2017, at CERN-SPS.
In the near future, new detector modules will be assembled with dedicated MICROROC
embedded electronics, developed for SDHCAL applications. This would be a crucial step
towards the integration of RPWELL sampling elements into a full SDHCAL prototype.

Speaker: Luca Moleri (Weizmann Institute of Science (IL))

Chef17_presentation.pdf

Break: Coffee

DAQ & Monitoring

Convener: Roman Poeschl (Universite de Paris-Sud 11 (FR))

51 A generic data acquisition software framework, EUDAQ2

The data acquisition software, EUDAQ1, was originally developed to read out
data from beam telescope systems. This was successfully used in many
beam tests in which an external position reference was required. The
software has recently undergone a significant upgrade, EUDAQ2, ensuring that
it is agnostic to the hardware and is a generic, modular system for use by
many detectors, including calorimeters. The software can run in different
triggering or event building modes and combine the data to produce a common
event. EUDAQ2 is also ideal as an overarching software that links to
individual detector DAQ systems and so can ease the integration of multiple
detectors for data taking. The system has been verified in a beam test
involving the analogue hadronic calorimeter, a development within the CALICE
collaboration which carries out R&D on linear collider calorimeters, and the
beam telescope; these have very different timing and readout structures. The
software was also successfully used in a beam test of the ATLAS inner tracker
upgrade. The EUDAQ2 software has been developed within the AIDA-2020 EU
programme to provide a common framework for linear collider beam tests, but
can also be used by other systems or project. The software is now released,
freely available and ready for use.

Speaker: Dr Yi Liu (DESY (DE) / IHEP (CN))

liuyi171004.pdf

52 A modern and versatile data-acquisition package for calorimeter prototypes test-beams: H4DAQ

The upgrade of the calorimeters for the HL-LHC or for future colliders requires an extensive programme of tests to qualify different detector prototypes with dedicated test beams. A common data-acquisition system (called H4DAQ) was developed for the H4 test beam line at the North Area of the CERN SPS in 2014 and it has since been adopted by an increasing number of teams involved in the CMS experiment and AIDA groups. Several different calorimeter prototypes and precision timing detectors have used H4DAQ from 2014 to 2017, and it has proved to be a versatile application, portable to many other beam test environments (the CERN beam lines: EA-T9 at the PS, H2 and H4 at the SPS, and at the INFN Frascati Beam Test Facility). The H4DAQ is fast, simple, modular and can be configured to support different setups. The different functionalities of the DAQ core software are split into three configurable finite state machines: the data readout, run control, and event builder. The distribution of information and data between the various computers is performed using ZEROMQ (0MQ) sockets. Different plugins are available to read different types of hardware, including VME crates with different types of boards, PADE boards, custom front-end boards and beam instrumentation devices. The raw data are saved as root files, using the CERN c++ root libraries. A Graphical User Interface, based on the python gtk libraries, is used to operate the H4DAQ and integrated data quality monitoring (DQM), written in c++, allows for fast processing of the events for quick feedback to the user. The 0MQ libraries are available as well for the National Instruments LabVIEW program. This facilitates communication with existing instrumentation and detector control systems, via commands issued by the H4DAQ GUI. The design, functionality and operational experience with the H4DAQ system will be described in this talk.

Speaker: Andrea Carlo Marini (Massachusetts Inst. of Technology (US))

2017_10_02_CHEF_H4DAQ.pdf

53 DQM4HEP: A generic Data Quality Monitoring for High Energy Physics

Online Data Quality Monitoring (DQM) is a central tool for the good operation of High Energy Physics experiments. Most of these experiments develop their own DQM solutions on top of the Event Data Model (EDM) specific to their detector. This leads to a strong dependency on the data format and make the reusability of the DQM tools for other detectors difficult.

We developed a generic online monitoring framework, independent of the EDM and data type, called DQM4HEP. It is designed for experiments ranging from table top size to large multi-detector test beams set-ups. To illustrate the flexibility of these tools, dedicated implementations, including physics analysis, for three of the CALICE1 collaboration prototypes SDHCAL2, AHCAL3 and SiWECAL4) were tested during test-beam campains at CERN SPS and DESY2 facilities. All three detectors use the same EDM, but different data acquisition systems and data formats.

After presenting the software architecture, the three specific detector implementations and results obtained during test-beam are shown. We finally discuss the ongoing development and future evolution planned for the framework.

1Calorimeter for linear collider experiment
2Semi-digital hadronic calorimeter
3Analog hadronic calorimeter
4Silicon-tungstene electromagnetic calorimeter

Speakers: Antoine Pingault (Ghent University (BE)), Remi Ete (DESY), Remi Ete (Universite Claude Bernard-Lyon I (FR))

DQM4HEP_CHEF2017.pdf

54 Pyrame3, an online framework for Calice SiW Ecal

Pyrame3 is the new version of the Pyrame framework, with emphasize on the online data treatment and the complex tasks scripting. A new mechanism has been implemented to allow any module to treat and publish data in real time. This data is made available to any requesting module. A circular buffer mechanism allows to break the real-time constraint and to serve the slower programs in a generic subsampling way. On the other side, a programming facility called event-loop has been provided in C/C++ language to ease the development of monitoring programs. On the Ecal prototype, the acquisition chain launches a bunch of online decoders that makes available raw data plus some basic reconstruction data (true coordinate, true time, data quality tags...). With the event-loop, it is now really very easy to implement new online monitoring programs. On the other side, the scripting mechanism has been enhanced to provide complete control of the detector to the scripts. This way, we are able to script and monitor complex behaviours like position or energy scanning, calibrations or data driven reconfigurations.

Speaker: Frederic Bruno Magniette (Centre National de la Recherche Scientifique (FR))

pyrame3.pdf

Break: Lunch

Mechanics & services

Convener: Maria Fouz Iglesias (Centro de Investigaciones Energéti cas Medioambientales y Tecno)

55 Cooling system R&D and end-caps geometry

The ILD silicon-tungsten electromagnetic calorimeter (ILD Si-W ECAL) is a sampling calorimeter with tungsten absorber and highly segmented silicon layers to achieve precise jet energy measurements by particle flow concept. In this context, the LPSC-Grenoble is involved in the R&D activities in order to design an electromagnetic calorimeter for the International Large Detector (ILD). Our developments focus on the design of the fastening and cooling systems. And a particular effort has been made to the design of the mechanics, the tooling and integration of the end-caps.

Speaker: Julien Giraud (LPSC)

ECAL_Endcaps-LPSC-CHEF_Meeting-Lyon-2017-10-05.pdf

56 Precision Mechanics for Calorimeter Structures

In the context of calorimetry R&D activities developed in the CALICE Collaboration, in synergy with the ILD experiment, and in the AIDA2020 project, one of the important goals is the construction of a new prototype of the Semi-digital Hadron Calorimeter (SDHCAL) with large chambers (similar to the largest proposed for the ILD) using new electronics and a mechanical structure built with the final procedures. This is one of the CALICE milestones in order to address the issues related to build a real detector fulfilling the demands of compactness and hermeticity and to prove its viability.
The compactness and the minimization of the dead spaces are intimately related with the design of the calorimeter absorber, which is also the support structure of the calorimeter modules. It requires to be able of producing absorber plates with very high planarity (less than 1mm) and assembly the structure with the lower deformations possible. For the SDHCAL the material of the absorber is stainless steel.
The use of bolts to fix the absorber plates together has been very common in hadronic segmented calorimeters, but with the very big modules proposed for the ILD, big bolts must be used, resulting on extra dead space that would deteriorate the calorimeter performance. Those dead spaces could be reduced by using welding but the disadvantage is the extra deformations the standard welding usually introduces. The use of electron beam welding could be a solution that is under investigation now.
The high accuracy on planarity needed for the plates is impossible to find in the standard market, mechanizing the raw plates to such planarity is too costly in terms of time and price. Roller leveling procedure has been envisaged as a cheaper, faster and high quality procedure.
In this talk, together with the design of the mechanical structure, the description of the techniques used (roller leveling and electron beam welding) and the obtained results with several small prototypes will be presented. Results obtained till now are promising, and even if this work is guide having in mind the ILD detector all these techniques could be used for any other hadronic calorimeter using stainless steel as absorber material.

Speaker: Enrique Calvo Alamillo (Centro de Investigaciones Energéti cas Medioambientales y Tecno)

CHEF2017_Lyon_EnriqueCalvo_v3.pdf

57 Dead zone analysis of ECAL barrel modules under static and dynamic loads

The ILD silicon-tungsten electromagnetic calorimeter (ILD Si-W ECAL) is a sampling calorimeter with tungsten absorber and highly segmented silicon layers to achieve precise jet energy measurements by particle flow concept. In this context, we started to study the impact of environmental loads on the Electromagnetic CALorimeter (ECAL) barrel detector. This ECAL barrel consists of several independent modules which are mounted on the Hadronic CALorimeter (HCAL) barrel itself mounted on the cryostat coil and the yoke. We need to estimate the gap required for ECAL modules assembly and operation to avoid mechanical contacts over the barrel lifetime. In the meantime, we need to minimize those gaps to reduce dead spaces and optimize detector hermeticity. The aim is to study the gap between ECAL barrel modules. To do so, we performed several FE static analysis with two different HCAL barrel designs. Moreover, because of the implantation site of the whole project in Japan, seismic analysis were carried out in addition to static ones. This article shows results of this analysis done with the FE method in ANSYS. First results show impacts of HCAL design on the ECAL modules motion in static load. The second part dedicated to seismic approach on a larger model (including yoke and cryostat) gives additional results on earthquake consequences.

Speaker: Thomas Bruno Pierre-Emile (Centre National de la Recherche Scientifique (FR))

Dead zone analysis of ECAL barrel modules PIERRE-EMILE Thomas.pdf

Dead zone analysis of ECAL barrel modules PIERRE-EMILE Thomas.pps

timing

Convener: Yi Wang (Tsinghua University)

58 Scintillator materials of garnets for a fast timing in a harsh radiation environment of collider experiments

In the last 40 years, use of scintillation inorganic materials based calorimeters has played a crucial role in the discovery of matter properties and contributed to a continuous progress in this technique. Physicists had built a variety of detectors: small detectors based on NaI(Tl), CsI(Na), BaF2, PbF2, and Bi4Ge3O12 and large detectors such as the electromagnetic calorimeter of CMS, consisting of 11 m3 of PbWO4 scintillator crystals.
The announcement of the LHC upgrade and FCC projects, in order to significantly increase luminosity at the experimental facilities, has renewed interest to the radiation tolerant inorganic scintillating crystals allowing suppression of pile-up by fast timing techniques.
Ce doped high light yield oxide scintillation materials have been recognised to be radiation tolerant to different kinds of ionising radiation, including gammas, high energy protons and neutrons [1]. Scintillation band of garnet crystals peaks in 520-560 nm spectral range, what pretty good matches SiPM spectral sensitivity. Moreover, time resolution in the measurements using multi-doped garnets was found substantially better. This behaviour was demonstrated for the first time at small energy release using 511 keV gamma-rays from 22Na source [2], when coincidence time resolution with full width at half maximum 233 ps was measured. At high energy deposit, when high energy charged particles have been used to excite the crystal, the samples yielded a better single device time resolution of 30.5 ps sigma [3]. Technology of the crystals under consideration is well developed, for different purposes, the different kinds of garnets are produced by tons.
Here we compare performance of three garnet crystals doped with Ce and co-doped with different ions: Y3Al5O12, Y3Al1.25Ga3.75O12 and Gd3Al2Ga3O12. Co-doping allows to control dynamics of the free carriers in the crystals and, at the certain conditions, to shift luminescence build up process in a sub-picosecond domain. A change of the scintillation properties in the operational temperature range from +20 to -40oC is discussed. Potential of the garnet type materials in different construction of calorimetric cells is debated.

References
1. P.Lecoq, A.Gektin, M.Korzhik, Inorganic Scintillators for detecting Systems, Springer, 2017, P.408.
2. M. Lucchini et al.,  NIM A 816 (2016) 176-183.
3. M.T. Lucchini, S. Gundacker, P. Lecoq, A. Benaglia, M. Nikl, K. Kamada, A. Yoshikawa and E. Auffray, NIM A 852 (2017) 1-9.

Speaker: Mikhail Korjik (Byelorussian State University (BY))

Korjik-5-10-2017-fin.pdf

59 Prospects for a precision timing upgrade of the CMS PbWO crystal electromagnetic calorimeter for the HL-LHC

The upgrade of the Compact Muon Solenoid (CMS) crystal electromagnetic calorimeter (ECAL), which will operate at the High Luminosity Large Hadron Collider (HL-LHC), will achieve a timing resolution of around 30 ps for high energy photons and electrons. In this talk we will discuss the benefits of precision timing for the ECAL event reconstruction at HL-LHC. Simulation studies focused on the timing properties of PbWO_4 crystals, as well as the impact of the photosensors and the readout electronics on the timing performance, will be presented. Test beam studies intended to measure the timing performance of the PbWO_4 crystals with different photosensors and readout electronics will be shown.

Speaker: Andrea Massironi (Northeastern University (US))

Oct-05_CHEF_ECAL_Massironi.pdf

60 A High-Granularity Timing Detector (HGTD) in ATLAS: Performance at the HL-LHC

The expected increase of the particle flux at the high luminosity phase of the LHC (HL-LHC) with instantaneous luminosities up to L ≃ 7.5 × 1034 cm−2 s−1 will have a severe impact on the ATLAS deetctor performance. The pile-up is expected to increase on average to 200 interactions per bunch crossing resulting in a vertex density that can be larger than 1.5 per mm.
The reconstruction and performance for electrons, photons, jets and transverse missing energy will be severely degraded in the end-cap and forward region, where the liquid Argon based electromagnetic calorimeter has coarser granularity compared to the central region. The High Granularity Timing Detector (HGTD) is proposed in front of the liquid Argon end-cap calorimeters for pile-up mitigation. Using the high granularity and the excellent timing capabilities of the detector with 30 ps per MIP, electron and jet reconstruction (b tagging) are presented as well as the impact on the pileup jet suppression and missing ET. The expected improvement in performance is particularly relevant for vector-boson processes.

Speaker: Nikola Makovec (LAL-Orsay (FR))

2017_10_CHEF_HGTDPerf.pdf

Break: Coffee

Reconstruction & PFA

Convener: Henri Videau (Laboratoire Leprince-Ringuet (LLR)-Ecole Polytechnique)

61 Software compensation and particle flow

The Particle Flow approach to calorimetry requires highly granular calorimeters and sophisticated software in order to reconstruct and identify individual particles in complex event topologies. Within the CALICE collaboration, several concepts for highly granular calorimeters are studied. The Analog Hadron Calorimeter (AHCAL) concept is a sampling calorimeter of tungsten or steel absorber plates and plastic scintillator tiles read out by silicon photomultipliers (SiPMs) as active material. The high calorimeter granularity can also provide a discrimination of the electromagnetic sub-showers in hadron showers. This discrimination can be utilised in an offline weighting scheme, the so-called software compensation technique, to improve the energy resolution for single particles.
The software compensation techniques developed on the CALICE AHCAL data have been
applied to full jet reconstruction using the PandoraPFA particle flow algorithm in
simulated events for the ILD detector concept for the ILC. The impact of software
compensation in the HCAL on PFA performance, and the dependence of this
performance on the granularity of the detector will also be discussed.

Speaker: Katja Krueger (Deutsches Elektronen-Synchrotron (DE))

SoftwareCompensation_CHEF_2017.pdf

62 An introduction to the particle flow algorithm for ILC, ArborPFA

The physics research on the future International Linear Collider(ILC) needs both state-of-the-art detectors and dedicated software with high performance. In this article, a software to reconstruct final state particles in the jet environment, ArborPFA, is elaborated. Using multiple pattern recognition algorithms and the high granularity of calorimeters, particles are reconstructed by re-building their original showers as oriented trees. After a successful implementation for the SDHCAL prototype, the algorithms have been ported to the entire ILD detector. Followed by describing the pattern recognition algorithms, local energy corrections due to the detector geometry are presented. The physics performance of the ArborPFA algorithm on di-jet events is finally discussed.

Speaker: Bo Li (Centre National de la Recherche Scientifique (FR))

CHEF2017_BoLi.pdf

63 Separation of two electromagnetic or electromagnetic-hadronic showers and properties of hadronic interactions in SiW ECAL

CALICE collaboration is developing highly granular calorimeters suitable for individual
reconstruction of particles in the jets and for Particle Flow Algorithms. Such calorimeters
should provide the best jet energy resolution at future high energy e + e - colliders. At high jet
energies, typically above 100 GeV, the jet particle showers start to overlap, and the
resolution is determined by the ability to separate them. Here, we present the results on the
separation of two overlapping electromagnetic or electromagnetic - hadronic showers
obtained with CALICE physical prototypes (silicon-tungsten, SiW ECAL and Analog
HCAL) and using International Large Detector (ILD) Monte Carlo. We use three available
reconstruction programs (Pandora, Garlic and Arbor).
In addition, we report on the study of hadron interactions in CALICE SiW ECAL physical
prototype based on a simple algorithm finding tracks of secondary particles. We define
several observables to compare data and Monte Carlo, the agreement is always within 20%.

Speaker: Kostiantyn Shpak (Centre National de la Recherche Scientifique (FR))

CHEF2017_shpak_V3.pdf

64 PFA Oriented Calorimeter: Performance and Optimization for CEPC

Speaker: Manqi Ruan (Chinese Academy of Sciences (CN))

JER-v2.pdf

Friday, 6 October

test beam results & analysis

Convener: Maria Fouz Iglesias (Centro de Investigaciones Energéti cas Medioambientales y Tecno)

65 Development of Radiation-Hard Scintillators and Wavelength-Shifting Fibers

Future circular and linear colliders as well as the Large Hadron Collider in the High-Luminosity era have been imposing unprecedented challenges on the radiation hardness of particle detectors that will be used for specific purposes e.g. forward calorimeters, beam and luminosity monitors. We perform research on the radiation-hard active media for such detectors, particularly calorimeters, in two distinct categories: Quartz plates coated with thin, radiation-hard organic or inorganic compounds, and intrinsically radiation-hard scintillators. In parallel to the effort on identifying radiation-hard scintillator materials, we also perform R&D on radiation-hard wavelength shifting fibers in order to facilitate a complete active medium for detectors under harsh radiation conditions.

Here we describe the recent advances in the developments of radiation-hard scintillators and wavelength shifting fibers. We will discuss recent and projected measurements and future directions in development of radiation-hard active media.

Speaker: David Winn (Fairfield University (US))

CHEF17_Winn_RadHard_v1.pdf

66 Construction and beam-tests of silicon-tungsten prototype modules for the CMS High Granularity Calorimeter for HL-LHC

As part of its HL-LHC upgrade program, CMS is developing a High Granularity Calorimeter
(HGCAL) to replace the existing endcap calorimeters. The HGCAL will be realised as a
sampling calorimeter, including an electromagnetic compartment comprising 28 layers of
silicon pad detectors with pad areas of 0.5 - 1.0 cm 2 interspersed with absorbers.
Prototype modules, based on 6-inch hexagonal silicon pad sensors with 128 channels, have
been constructed and include many of the features required for this challenging detector.
In 2016, beam tests of sampling configurations made from these modules have been
conducted both at FNAL and at CERN using the Skiroc2 front-end chip (designed for the
CALICE experiment for ILC).
This year, the setup is extended with CALICE’s AHCAL prototype and it is further tested in
dedicated beam tests at CERN. There, the new Skiroc2-CMS front-end chip is used for the
first time.
We present final results from our studies in 2016, including noise performance, calibration
with MIPs, energy and position resolution as well as precision timing-measurements.
Furthermore, the extended setup in 2017 is discussed and first results from laboratory and
beam tests with electrons and pions are shown.

Speaker: Thorben Quast (Rheinisch Westfaelische Tech. Hoch. (DE))

CMS_HGCAL_TB_Quast_10_06_final_animated.pdf

CMS_HGCAL_TB_Quast_10_06_final.pdf

67 First results from SiPM+QIE11 readout in CMS for the pp collisions

We report on the first LHC collision data taken with a 20 degree wedge of
the CMS Hadron Calorimeter Endcap instrumented with SiPMs and the QIE
ASIC version 11 front-end chip.
Operational experience is reported on temperature and gain stability of the
SiPMs. The performance of the front-end ASIC and digital readout are also
presented. The light loss from the darkening of the CMS HCAL endcap
scintillator is shown to be mitigated by the increased PDE of the SiPM and
higher overall S/N of the front-end upgrade. We compare the performance of
the Phase I front-end upgrade electronics with the previous HPD-based
front-end system performance with LHC collision data collected in 2017.

Speaker: Kelvin Mei (Princeton University)

CHEF2017_KMei_First_Results_from_SiPM_and_QIE11_Readout_in_CMS_for_pp_Collisions.pdf

68 Large-Area Silicon Detectors for the CMS High Granularity Calorimeter

During the so-called Phase-II Upgrade the CMS experiment at CERN will undergo significant improvements to cope with a 10-fold increase in luminosity of the High Luminosity LHC (HL-LHC) era. Especially the forward calorimetry will then suffer from very high radiation levels and intensified pile-ups in the detectors. Thus, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The ECAL and a large fraction of HCAL will consist of a sandwich structure with silicon as active detector material. The sensors will be of hexagonal shape, maximizing the available 8-inch wafer area. Each sensor consists between 100 and 300 individual pixels, each of 0.5 - 1 cm^2 in size without any common biasing structure. Biasing of the cells will be performed through the readout chip on module level, but poses several complications for the electrical characterization of the bare sensors in the lab. In this talk, the current status of the detector development is presented, including the different vendors which have an 8-inch production available. Moreover, radiation hardness studies and the construction of a dedicated test system to cope with the challenging testing of those sensors will be presented.

Speaker: Elias Pree (Austrian Academy of Sciences (AT))

CHEF-2017-HGC-PreeV2.pdf

69 Scintillator performance at low dose rates and low temperatures for the CMS High Granularity Calorimeter for HL-LHC

The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance, especially for forward calorimetry, and hallmarks the issue for future colliders. As part of its HL-LHC upgrade program, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters. The upgrade includes both electromagnetic and hadronic compartments, with the latter using a mixture of silicon sensors (in the highest radiation regions at high pseudorapidity) and scintillator as its active components. The scintillator will nevertheless receive large doses accumulated at low dose-rates, and will have to operate at low temperature - around -30 degrees Celsius. We discuss measurements of scintillator radiation-hardness, from in-situ measurements from the current CMS endcap calorimeters, from measurements taken in the collision hall using a special test setup, and measurements at low temperature and low dose-rate at gamma sources. We also discuss studies using a silicon photomultiplier (SiPM) placed directly on the scintillator for readout, instead of the use of more-conventional embedded wavelength-shifting fibres leading to SiPms.

Speaker: Francesca Ricci-Tam (University of Maryland (US))

RicciTam_ScintillatorPerformance.pdf

Break: Coffee

Simulation

Convener: Didier Lacour (LPNHE-Paris CNRS/IN2P3)

70 Simulation of the CMS electromagnetic calorimeter response at the energy and intensity frontier

The harsh radiation environment in which detectors will have to operate during the High Luminosity phase of The electromagnetic calorimeter (ECAL) of the CMS experiment at the LHC is a homogeneous calorimeter made of 75848 lead tungstate (PbWO_4) scintillating crystals, designed for high precision electron and photon energy measurements in hadron collisions at the TeV scale. The detailed simulation of the calorimeter response is crucial for physics analyses involving electrons, photons, jets or missing energy. The detector simulation has been tuned during the first LHC run, including a detailed description of the upstream material. The increase of centre of mass energy, bunch crossing rate and instantaneous luminosity in the second run has resulted in updated and improved data readout settings and reconstruction techniques. Furthermore ageing effects due to radiation, in particular noise increases in the photodetectors and crystal transparency losses, have caused a change of the calorimeter response. All of these effects have been taken into account in order to improve the simulation of the calorimeter response and to ensure that it describes the data well over time, notwithstanding the evolving conditions. In 2024 the ECAL will undergo an upgrade to cope with the high luminosity phase of the LHC (HL-LHC). The temperature of the calorimeter will be lowered to mitigate the ageing effects, the front-end electronics will be replaced with a faster version and the data will be read out in streaming mode towards the off-detector electronics. The fast PbWO 4 response time will be exploited to measure the timing of high-energy showers with high precision. A detailed simulation description of the crystal response is fundamental for the design of the detector electronics and to predict the performance for the energy and timing measurements. The techniques employed in tuning the simulation of the detector response for the present running conditions and for the upgrade will be presented.

Speaker: Alexander Ledovskoy (University of Virginia (US))

171006_chef_v2_ledovskoy.pdf

71 PFA Oriented ECAL Simulation and Geometry Optimization for the CEPC

The design and optimization of the Electromagnetic Calorimeter(ECAL) are crucial for the Circular Electron Positron Collider (CEPC) project, a proposed Higgs/Z factory with the total circumference of 100km. Following the reference design of the International Large Detector, a set of silicon-tungsten and scintillator-tungsten sampling ECAL geometries have been implemented into the Geant4 simulation, and a dedicated Particle Flow reconstruction, Arbor, has been adjusted to these geometries. Using full simulated-reconstructed samples, the performances of photon reconstructions, nearby electromagnetic(EM) showers separation and the reconstructions of physics events such as Higgs->γγ and Z->ττ have been quantified and compared at different ECAL geometries. Based on these analysis results, we checked and optimized the ECAL structure design for the CEPC project. Compared to the original design, the optimized geometry could reduce the number of read-out channels and maintains the same level performances on physics events reconstruction.

Speaker: Hang Zhao (Chinese Academy of Sciences (CN))

Hang_CHEF2017.pdf

72 New Developments in Geant4 Version 10 Series and Its Physics Validations

The Geant4 Collaboration released a new generation of the Geant4 simulation toolkit (version 10) in December 2013. Since then, the Collaboration continues to improve its physics and computing performance and usability. This presentation will survey the major improvements made since version 10.0. On the physics side, it includes new multiple scattering models, Auger atomic de-excitation cascade simulation, significant improvements in string models, radioactive decay model including isomer production, and an extension of the low-energy neutron model to protons and light ions. The Geant4 collaboration regularly performs validation and regression tests on all the physics models the toolkit offers. Validation tests compare results obtained with a specific Geant4 version, with data obtained by various experiments. Regression tests compare results of two or more versions of Geant4 for any observable. The Geant4 collaboration reconciles and organizes the validation materials in one central repository and makes this data easily available to both collaborators and the user community in general. This presentation will also survey the major observables regularly monitored, and introduce ways in which the user community could contribute to this validation process through providing their experimental data.

Speaker: Andrea Dotti (SLAC National Accelerator Laboratory (US))

CHEF2017(1).pdf

73 Recent progress of Geant4 electromagnetic physics for simulation of calorimeters

We report on recent progress in the Geant4 electromagnetic (EM) physics sub-packages.
New interfaces and models introduced in Geant4 10.3 (December, 2016) are already
tried in LHC applications and may be useful for any type of Monte Carlo simulation.
Additional developments for EM physics are already available with the recent public
version Geant4 10.4beta (June, 2017) and will be included in the next Geant4 10.4
(December, 2017).
Important developments for calorimetry applications were carried out for the modeling
of single and multiple scattering of charged particles. Corrections to scattering of
positrons and to sampling of displacement have been added to the Geant4 default Urban
model used for simulation of electrons and positrons. The alternative Goudsmit-
Saunderson (GS) model is based fully on theory, it was recently reviewed and re-written.
For testing of novel calorimeters we provide a configuration of electron scattering based
on the GS model or on the single scattering model (SS) instead of the Urban model. In
addition, an option may be used for GS and SS models when Mott corrections are enabled.
In this report, we will also present developments of EM models in view of the simulation
for the new FCC facility. The simulation of EM processes is important for optimization of
FCC interaction region and for study of various conceptions of FCC detectors. This
requires an extension of validity of EM models for energies higher than the ones used for
LHC experiments.
Important developments were recently carried out in low-energy EM models, which may
be of interest to various application domains including fine grain calorimeters. In
particular, an option to simulate full fluorescence and Auger cascades is added, triplet
production in gamma conversion is introduced and the model of photoelectric effect is
reviewed and updated.

Speaker: Prof. Vladimir Ivantchenko (CERN)

Geant4EMPhys.pdf

Break: Lunch

Simulation

Convener: Vladislav Balagura (Centre National de la Recherche Scientifique (FR))

74 Simulation of the CALICE Semi-Digital Hadronic Calorimter

The CALICE Semi-Digital Hadronic Calorimeter technological prototype is a sampling calorimeter using Glass Resistive Plate Chamber detectors with a three-threshold readout as the active medium. This technology is one of the two options proposed for the hadronic calorimeter of the International Large Detector for the International Linear Collider. The prototype was exposed to beams of muons, electrons and pions of different energies at the CERN Super Proton Synchrotron. To be able to study the performance of such a calorimeter in future experiments it is important to ensure reliable simulation of its response. The simulation of this prototype and the digitisation procedure are presented. Comparisons between beam test data and the simulation, covering detector response and shower shapes, are also discussed. Finally a method allowing the reconstruction of track segments within hadronic showers is presented and tested using data and the simulation.

Speaker: Arnaud Steen (National Taiwan University (TW))

sdhcal-asteen.pdf

75 Simulation studies of reconstruction of hadron shower direction in INO ICAL detector

The Iron Calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is a proposed 50 kton magnetised iron detector optimised for the detection of atmospheric muon neutrinos (and anti-neutrinos). These neutrinos interact with the target iron via both charged current (CC) and neutral current (NC) interactions. The CC interactions produce a muon and hadrons in the final state, which are observed as a track and shower respectively in the detector; in contrast, only a hadron shower is visible in NC events since the secondary neutrino is invisible. We present a GEANT4 based simulation study of neutrino events generated using the NUANCE neutrino generator to obtain the direction of the hadron shower in both types of interactions. (The calibration of the hadron energy from the shower has been studied earlier). We implement two methods, namely the orientation matrix method (OMM) and the raw hit method (RHM) to reconstruct the shower direction. While the OMM requires information about the interaction vertex obtained from muon track reconstruction and is applicable only to CC events, the RHM requires only the hit positions and timings (and no vertex information) and is thus applicable for both CC and NC events. The former performs better owing to the information on the vertex: a direction resolution of 16◦–7◦ is obtained for hadron showers with energy in the range E′h = 0.5–15 GeV which are produced in the direction cosθ′h = [0.8, 1]. In contrast, the RHM achieves a relatively poorer resolution of 18◦–10◦ for the same data set, and a similar resolution of 18◦–11◦ for NC events in the same energy and angle bins.

Speaker: Lakshmi S Mohan (India Based Neutrino Observatory (INO) & IMSc Chennai)

HA-lsm.pdf

76 Simulation of Secondary Emission Calorimeter for Future Colliders

Ever increasing collision energies in current and future colliders demand for radiation hard calorimeters. Calorimeters based on secondary electron emission process from dynode metals was proposed in 1990s as radiation hard alternative to overcome this difficulty. Since the discovery of secondary emission of electrons from metal surfaces, there has been many approaches to quantify this process by using semi-empirical models, including Monte Carlo studies. These Monte Carlo studies, however, usually do not include secondary emission process as a part of physics, governing the shower development and the probabilistic nature of the emission process. In this study, we present a Geant4 calorimeter simulation based on a newly developed physics class, which was derived from a probabilistic approach found in the literature. By developing this physics class inside Geant4 we were able to determine the yield and energy spectrum of secondary emission electrons from metal surfaces. We were also able to determine the calorimeter response to energetic particles by using the showers they create inside the calorimeter layers consisting of dynode structures. We first provide a comparison between data and simulation of a thin foil for the yield and secondary electron energy spectrum. We then give response, linearity, and resolution for a generic sampling calorimeter based on a secondary emission electron process together with results from a scintillating sampling calorimeter for comparison.

Speakers: Dr Asli Yetkin (stanbul Bilgi University), Elif Asli Yetkin (Bogazici University (TR))

AsliYetkin_CHEF2017.pdf

Institutional: Farewell and closing

77 Concluding remarks

Speaker: Henri Videau (Laboratoire Leprince-Ringuet (LLR)-Ecole Polytechnique)

CHEF_concluding_remarks.pdf

78 CHEF2017 Farwell

Speaker: Imad Laktineh (Universite Claude Bernard Lyon I (FR))