During 2003 test beam session for ATLAS Tile Calorimeter a monitoring program has been developed to ease the setup of correct running condition and the assessment of data quality. The program has been built using the Online Software services provided by the ATLAS Online Software group. The first part of this note contains a brief overview of these services followed by the full description of Tile Calorimeter monitoring program architecture and features. Performances and future upgrades are discussed in the final part of this note.
The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the most central region of the ATLAS experiment at the LHC. It is a key detector for the measurement of hadrons, jets, tau leptons and missing transverse energy. The TileCal calibration system comprises radioactive source, laser and charge injection elements and it allows to monitor and equalize the calorimeter response at each stage of the signal production, from scintillation light to digitization. This contribution presents a brief description of the different TileCal calibration systems as well as the latest results on the…
The front face of the CDF central calorimeter is being equipped with a new Preshower detector, based on scintillator tiles read out by WLS fibers, in order to cope with the luminosity increase provided by the Main Injector during the Tevatron's Run II data taking. A light yield of about 40 pe/MIP at the tile exit was obtained, exceeding the design requirements.
TileCal is the hadronic calorimeter covering the most central region of the ATLAS experiment at the LHC. This sampling calorimeter uses iron plates as absorber and plastic scintillating tiles as the active material. A multi-faceted calibration system allows to monitor and equalize the calorimeter response at each stage of the signal production, from scintillation light to digitization. This calibration system is based on signal generation from different sources: a Cs radioactive source, laser light, charge injection and minimum bias events produced in proton-proton collisions. A brief descript…
This article describes the Laser calibration system of the Atlas hadronic Tile Calorimeter that has been used during the run 1 of the LHC. First, the stability of the system associated readout electronics is studied. It is found to be stable with variations smaller than 0.6 %. Then, the method developed to compute the calibration constants, to correct for the variations of the gain of the calorimeter photomultipliers, is described. These constants were determined with a statistical uncertainty of 0.3 % and a systematic uncertainty of 0.2 % for the central part of the calorimeter and 0.5 % for …
The upgrade of the DA$Φ$NE machine layout requires a modification of the size and position of the inner focusing quadrupoles of KLOE-2 thus asking for the realization of two new calorimeters covering the quadrupoles area. To improve the reconstruction of $K_L\to 2π^0$ events with photons hitting the quadrupoles a calorimeter with high efficiency to low energy photons (20-300 MeV), time resolution of less than 1 ns and space resolution of few cm, is needed. To match these requirements, we are designing a tile calorimeter, QCALT, where each single tile is readout by mean of SiPM for a total gran…
The CALICE collaboration is currently developing an engineering prototype of an analog hadron calorimeter for a future linear collider detector. It is based on scintillating tiles that are individually read out by silicon photomultipliers. The prototype will contain about 2500 detector channels, which corresponds to one calorimeter layer and aims at demonstrating the feasibility of building a detector with fully integrated front-end electronics. The concept and engineering status of the prototype, as well as results from the DESY test setups are reported here.
The Tile Calorimeter (TileCal) of the ATLAS experiment at the LHC is the central hadronic calorimeter designed for reconstruction of hadrons, jets, tau-particles and missing transverse energy. TileCal is a scintillator-steel sampling calorimeter and it covers the region of $|η| < 1.7$. The scintillation light produced in the scintillator tiles is transmitted by wavelength shifting fibers to photomultiplier tubes (PMTs). The analog signals from the PMTs are amplified, shaped and digitized by sampling the signal every 25 ns. The TileCal frontend electronics reads out the signals produced by abou…
The Tile PreProcessor (TilePPr) is the core element of the Tile Calorimeter (TileCal) off-detector electronics for High-luminosity Large Hadron Collider (HL-LHC). The TilePPr comprises FPGA-based boards to operate and read out the TileCal on-detector electronics. The Tile Computer on Module (TileCoM) mezzanine is embedded within TilePPr to carry out three main functionalities. These include remote configuration of on-detector electronics and TilePPr FPGAs, interface the TilePPr with the ATLAS Trigger and Data Acquisition (TDAQ) system, and interfacing the TilePPr with the ATLAS Detector Contro…
The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment at LHC. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibers to photo-multiplier tubes (PMTs), located in the outer part of the calorimeter. The readout is segmented into about 5000 cells, each one being read out by two PMTs in parallel. To calibrate and monitor the stability and performance of the full readout chain during the data taking, …
Imaging hadronic calorimeters with scintillator readout use small scintillator tiles individually read out by silicon photomultipliers to achieve the necessary granularity needed for sophisticated reconstruction algorithms at future collider detectors. For a second generation prototype of the CALICE analog HCAL new, 3 mm thick scintillator tiles with an embedded wavelength shifting fiber and new photon sensor from CPTA are being fabricated. The availability of blue-sensitive SiPMs also allows fiberless coupling of the photon sensor to the tile, a technique requiring modified geometries to achi…
The Analogue Hadron Calorimeter (AHCAL) is being developed within the CALICE collaboration for experiments at a future lepton collider. It is a sampling calorimeter with alternating layers of steel absorber plates and plastic scintillator tiles as active material. In the SiPM on tile design, the tiles are directly coupled to silicon photomultipliers (SiPMs). The front-end electronics are integrated into the active layers of the calorimeter. They are designed for low power consumption by rapidly power cycling according to the beam structure of a linear accelerator. In 2017 and 2018, a new large…
The SiPM-on-tile technology, consisting of plastic scintillator tiles with typical sizes of a few cm$^2$ mounted on top of SiPMs, has been developed within the CALICE collaboration to enable automatized mass production of active elements for scintillator-based highly granular calorimeters. We present a study of the impact of misalignment of the scintillator tile with respect to the photon sensor on the response uniformity and on the absolute light yield for square, hexagonal and rhomboidal scintillator tiles of different sizes. A misalignment results in the formation of a dipole asymmetry of t…
The upgrade of the DA$Φ$NE machine layout requires a modification of the size and position of the inner focusing quadrupoles of KLOE$^2$ thus asking for the realization of two new calorimeters covering the quadrupoles area. To improve the reconstruction of $K_L\to 2π^0$ events with photons hitting the quadrupoles, a tile calorimeter, QCALT, with high efficiency to low energy photons (20-300 MeV), time resolution of less than 1 ns and space resolution of few cm, is needed. We propose a tile calorimeter with a high granularity readout corresponding to about 2500 silicon photomultipliers (SiPM) o…
This article describes the design, construction and use of a calibration and monitoring system, based on movable 137Cs gamma-ray sources, for the ATLAS Tile Calorimeter (TileCal). The sources, propelled by a water-based liquid through tubes that traverse all the calorimeter's cells, produce signals that precisely characterise the response of each tile, thereby providing very granular and accurate data on the response of TileCal to particles. The system has been used to guide and control the quality of the optical instrumentation of all TileCal modules, to set and equalise the dynamic range of …
The Analogue Hadron Calorimeter (AHCAL) developed by the CALICE collaboration is a scalable engineering prototype for a Linear Collider detector. It is a sampling calorimeter of steel absorber plates and plastic scintillator tiles read out by silicon photomultipliers (SiPMs) as active material (SiPM-on-tile). The front-end chips are integrated into the active layers of the calorimeter and are designed for minimizing power consumption by rapidly cycling the power according to the beam structure of a linear accelerator. 38 layers of the sampling structure are equipped with cassettes containing 5…
The CALICE collaboration is currently developing an engineering prototype of an analog hadron calorimeter for a future linear collider like the ILC. One main task of this prototype is to demonstrate the feasibility of building a realistic detector with fully integrated front-end electronics. To reach the required high jet energy resolution the detector is based on highly segmented read out layers. The signals are sampled by scintillating tiles that are individually read out by silicon photomultipliers. The readout chips are integrated into the calorimeter layers and are optimized for minimal p…
The Tile Calorimeter (TileCal) is the central hadronic calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC). The LHC is scheduled to undergo a major upgrade, in 2022, for the High Luminosity LHC (HL-LHC). The ATLAS upgrade program for high luminosity is split into three phases: Phase-0 occurred during $2013-2014$ and prepared the LHC for Run 2; Phase-I, foreseen for 2019, will prepare the LHC for Run 3, whereafter the peak luminosity reaches $2-3 \times 10^{34}$ cm$^{2}s^{-1}$; finally, Phase-II, which is foreseen for 2024, will prepare the collider for the HL-LHC operation (…
Precision calorimetry using highly granular sampling calorimeters is being developed based on the particle flow concept within the CALICE collaboration. One design option of a hadron calorimeter is based on silicon photomultipliers (SiPMs) to detect photons generated in plastic scintillator tiles. Driven by the need of automated mass assembly of around ten million channels stringently required by the high granularity, we developed a design of scintillator tiles directly coupled with surface-mounted SiPMs. A cavity is created in the center of the bottom surface of each tile to provide enough ro…
The CALICE collaboration is presently constructing a test hadron calorimeter (HCAL) with 7620 scintillator tiles read out by novel photo-detectors - Silicon Photomultipliers (SiPMs). This prototype is the first device which uses SiPMs on a large scale. We present the design of the HCAL and report on measured properties of more than 10 thousand SiPMs. We discuss the SiPM efficiency, gain, cross-talk, and noise rate dependence on bias voltage and temperature, including the spread in these parameters. We analyze the reasons for SiPM rejection and present the results of the long term stability stu…
The Tile hadronic calorimeter of the ATLAS detector has undergone extensive testing in the experimental hall since its installation in late 2005. The readout, control and calibration systems have been fully operational since 2007 and the detector successfully collected data from the LHC single beams in 2008 and first collisions in 2009. This paper gives an overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data. The detector operation status, noise characteristics and performance of the calibration system…
The Tile Calorimeter (TileCal) is one detector of the ATLAS experiment at the Large Hadron Collider (LHC). TileCal is a sampling calorimeter made of steel plates and plastic scintillators which are readout using approximately 10,000 PhotoMultipliers Tubes (PMTs). In 2024, the LHC will undergo a series of upgrades towards a High Luminosity LHC (HL-LHC) to deliver up to 7.5 times the current nominal instantaneous luminosity. The ATLAS Tile Phase II Upgrade will accommodate detector and Data AcQuisition (DAQ) system to the HL-LHC requirements. The detector electronics will be redesigned using a n…
The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment. TileCal uses steel as absorber and plastic scintillators as active medium. The scintillators are read-out by the wavelength shifting fibres coupled to the photomultiplier tubes (PMTs). The analogue signals from the PMTs are amplified, shaped, digitized by sampling the signal every 25 ns and stored on detector until a trigger decision is received. The TileCal front-end electronics reads out the signals produced by about 10000 channels measuring energies ranging from about 30 Me…
The High Luminosity Large Hadron Collider (HL-LHC) will have a peak luminosity of $5\times10^{34} $cm$^{-2} $\,s$^{-1}$, five times higher than the design luminosity of the LHC. The hadronic ATLAS Tile Calorimeter TileCal) is a sampling calorimeter with steel as absorber and plastic scintillators as active medium. The light produced in the scintillating tiles is guided to photomultiplier tubes (PMTs), where analogue signals are produced to be shaped and conditioned before being digitized every 25\,ns. TileCal Phase-II Upgrade for the HL-LHC will allow the system can cope with the increased rad…
TileCal, the central hadronic calorimeter of the ATLAS detector is composed of plastic scintillators interleaved by steel plates, and wavelength shifting optical fibres. The optical properties of these components are known to suffer from natural ageing and degrade due to exposure to radiation. The calorimeter was designed for 10 years of LHC operating at the design luminosity of $10^{34}$cm$^{-2}$s$^{-1}$. Irradiation tests of scintillators and fibres have shown that their light yield decrease by about 10% for the maximum dose expected after 10 years of LHC operation. The robustness of the Til…
The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS detector at the LHC. It is a sampling calorimeter consisting of alternating thin steel plates and scintillating tiles. Wavelength shifting fibers coupled to the tiles collect the produced light and are read out by photomultiplier tubes. Currently, an analog sum of the processed signal of several photomultipliers serves as input to the first level of trigger. Photomultiplier signals are then digitized and stored on detector and are only transferred off detector once the first trigger acceptance h…
The basic prototype of a tile hadron calorimeter (HCAL) for the International Linear Collider (ILC) has been realised and extensively tested. A major aspect of the proposed concept is the improvement of the jet energy resolution by measuring details of the shower development and combining them with the data of the tracking system (particle flow). The prototype utilises scintillating tiles that are read out by novel Silicon Photomultipliers (SiPMs) and takes into account all design aspects that are demanded by the intended operation at the ILC. Currently, a new 12 layer prototype with about 340…
A selection of ATLAS liquid argon (LAr) calorimeter commissioning studies is presented. It includes a coherent noise study, a measurement of the quality of the ionization pulse shape prediction, and energy and time reconstruction analyses with cosmic and single beam signals.
ATLAS has chosen for its Hadronic End-Cap Calorimeter (HEC) the copper-liquid argon sampling technique with flat plate geometry and GaAs pre-amplifiers in the argon. The contruction of the calorimeter is now approaching completion. Results of production quality checks are reported and their anticipated impact on calorimeter performance discussed. Selected results, such as linearity, electron and pion energy resolution, uniformity of energy response, obtained in beam tests both of the Hadronic End-Cap Calorimeter by itself, and in the ATLAS configuration where the HEC is in combination with the…
The present article introduces a novel ASIC architecture, designed in the context of the ATLAS Tile Calorimeter upgrade program for the High-Luminosity phase of the Large Hadron Collider at CERN. The architecture is based on radiation-tolerant 130 nm Complementary Metal-Oxide-Semiconductor technology, embedding both analog and digital processing of detector signals. A detailed description of the ASIC is given in terms of motivation, design characteristics and simulated and measured performance. Experimental studies, based on 24 prototype units under real particle beam conditions are also prese…
A detector designed to measure early particle showers has been installed in front of the central CDF calorimeter at the Tevatron. This new preshower detector is based on scintillator tiles coupled to wavelength-shifting fibers read out by multi-anode photomultipliers and has a total of 3,072 readout channels. The replacement of the old gas detector was required due to an expected increase in instantaneous luminosity of the Tevatron collider in the next few years. Calorimeter coverage, jet energy resolution, and electron and photon identification are among the expected improvements. The final d…
During summer 2004, a testbeam for the ATLAS experiment was performed at CERN. A full slice of the ATLAS detector was tested with the final version of the acquisition electronics. In the talk presented at Calor06 conference, the ATLAS calorimeters response to high and low energy pions was presented.
We propose extending parallel fiber dual readout calorimetry to tiles, more applicable to many future experimental requirements, with superior energy resolution. Monte Carlo (MC) studies indicate that a tile dual calorimeter including an integral Cerenkov-compensated e-m front end and further longitudinal segmentation, not possible with parallel fibers, has equivalent or better resolution. Besides comparison and tuning with dual tile calorimeter data, a MC can be extended to study other dual and then multiple tile sensors including tiles with higher contrast to em-hadron shower fluctuations wi…
We present the optical data links for the ATLAS liquid argon calorimeter. The current status of the vertical cavity surface emitting laser failures, the up-to-date results in searching for the failure cause, experiences gained in the searching process, possible backup plans for the optical transmitters and the lessons learned are also discussed.
The CALICE collaboration is developing highly granular electromagnetic and hadronic calorimeters for detectors at future energy frontier electron-positron colliders. After successful tests of a physics prototype, a technological prototype of the Analog Hadron Calorimeter has been built, based on a design and construction techniques scalable to a collider detector. The prototype consists of a steel absorber structure and active layers of small scintillator tiles that are individually read out by directly coupled SiPMs. Each layer has an active area of $72 \times 72\,{\rm cm}^{2}$ and a tile siz…
We present light yield and uniformity measurements of square and hexagonal tiles read out with silicon photomultipliers via a Y11 wavelength-shifting fiber or directly from the side or from the center at the top face. All tiles are 3~mm thick and have an area of $\rm 9~cm^2$. The sides are wrapped with two layers of Teflon tape while top and bottom faces are covered with two layers of Tyvec paper. We further show the first light yield and uniformity measurements of ATLAS Tile Calorimeter (TileCal) tiles with MPPC readout. This study has been motivated by looking into a possible phase 3 upgrade…
The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the most central region of the ATLAS experiment at LHC. The TileCal readout consists of about 10000 channels. The ATLAS upgrade program is divided in three phases: The Phase~0 occurs during 2013-2014, Phase~1 during 2018-1019 and finally Phase~2, which is foreseen for 2022-2023, whereafter the peak luminosity will reach 5-7 x 10$^{34}$ cm$^2$s$^{-1}$ (HL-LHC). The main TileCal upgrade is focused on the Phase~2 period. The upgrade aims at replacing the majority of the on- and off-detector electronics so that all calorimeter sig…
The ATLAS hadronic Tile Calorimeter will undergo major upgrades to the on- and off-detector electronics in preparation for the High Luminosity program of the Large Hadron Collider (HL-LHC) in 2026, so that the system can cope with the HL-LHC increased radiation levels and out-of-time pileup. The on-detector electronics of the upgraded system will continuously digitize and transmit all photo-multiplier signals to the off-detector systems at a 40 MHz rate. The off-detector electronics will store the data in pipeline buffers, produce digital hadronic tower sums for the ATLAS Level-0 trigger syste…
With the successful construction and operation of a highly granular hadron calorimeter system, featuring approx. 22000 individually read out SiPM-on-tile channels, the CALICE collaboration has set the next milestone in proving the scalability of the concept for a future high energy linear collider experiment. For this large sample of photosensors a new approach of quality control was required to sufficiently characterise and monitor device parameters for both, test bench and in-situ beam test data. In the presence of temperature fluctuations during operation, it was possible to stabilise the S…
Measurements are presented of the reduction of signal output due to radiation damage for plastic scintillator tiles used in the hadron endcap (HE) calorimeter of the CMS detector. The tiles were exposed to particles produced in proton-proton (pp) collisions at the CERN LHC with a center-of-mass energy of 13 TeV, corresponding to a delivered luminosity of 50 fb$^{-1}$. The measurements are based on readout channels of the HE that were instrumented with silicon photomultipliers, and are derived using data from several sources: a laser calibration system, a movable radioactive source, as well as …
In 2002 the first combined beam test of the hadronic and electromagnetic liquid-argon endcap calorimeters of the ATLAS experiment took place at the SPS test beam at CERN. A total of 15 million events from electrons, muons and pions in the energy range from 6 to 200 GeV were recorded. The entire calibration chain, from digital filter weights, over calibration constants, to clustering and energy weights, as is relevant for the energy calibration of hadronic and electromagnetic showers in ATLAS was tested and applied to the beam test data. The calibration methods and first results for the combine…
The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two end-caps with electromagnetic, hadronic and forward calorimeters. The construction of the full calorimeter system is completed since mid-2004. The detector has been operated with LAr at nominal high voltage and fully equipped with readout electronics. Online software, monitoring tools and offline signal reconstruction have been developed for data collection and processing. Extensive tests with calibration pulses have been carried out, and the electronics calibration scheme for all 182468 c…
The high-luminosity phase of the Large Hadron Collider will provide 5-7 times greater luminosities than assumed in the original detector design. An improved trigger system requires an upgrade of the readout electronics of the ATLAS Liquid Argon Calorimeter. Concepts for the future readout of the 182,500 calorimeter cells at 40-80 MHz and 16-bit dynamic range and the developments of radiation-tolerant, low-noise, low-power, and high-bandwidth front-end electronic components, including preamplifiers and shapers, 14-bit ADCs, and 10-Gb/s laser diode array drivers, are presented in this paper.
TileCal is the central hadronic calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC). It is a sampling detector where scintillating tiles are embedded in steel absorber plates. The tiles are grouped forming cells, which are read-out on both sides by photomultiplier tubes (PMTs). The PMT digital samples are transmitted to the Read-Out Drivers (ROD) located in the back-end system for the events accepted by the Level 1 trigger system. The ROD is the core element of the back-end electronics and it represents the interface between the front-end electronics and the ATLAS overall Da…
The Phase-2 ATLAS upgrade for the High Luminosity Large Hadron Collider (HL-LHC) has motivated progressive redesigns of the ATLAS Tile Calorimeter (TileCal) read-out link and control board (Daughterboard). The Daughterboard (DB) communicates with the off-detector electronics via two 4.6 Gbps downlinks and two pairs of 9.6 Gbps uplinks. Configuration commands and LHC timing is received through the downlinks by two CERN radiation hard GBTx ASICs and propagated through Ultrascale+ FPGAs to the front-end. Simultaneously, the FPGAs send continuous high-speed readout of digitized PMT samples, slow c…
The purpose, design specifications, construction techniques, and testing methods are described for the high voltage feedthrough ports and filters of the ATLAS Liquid Argon calorimeters. These feedthroughs carry about 5000 high voltage wires from a room-temperature environment (300 K) through the cryostat walls to the calorimeters cells (89 K) while maintaining the electrical and cryogenic integrity of the system. The feedthrough wiring and filters operate at a maximum high voltage of 2.5 kV without danger of degradation by corona discharges or radiation at the Large Hadron Collider.
The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing performance, electronics noise, and gain stability are presented. High energy deposits from radiative cosm…
The CALICE analog HCAL is a highly granular calorimeter, proposed for the International Linear Collider. It is based on scintillator tiles, read out by silicon photomultipliers (SiPMs). The effects of gaps between the calorimeter tiles, as well as the non-uniform response of the tiles, in view of the impact on the energy resolution, are studied in Monte Carlo events. It is shown that these type of effects do not have a significant influence on the measurement of hadron showers.
This article documents the characteristics of the high voltage (HV) system of the hadronic calorimeter TileCal of the ATLAS experiment. Such a system is suitable to supply reliable power distribution into particles physics detectors using a large number of PhotoMultiplier Tubes (PMTs). Measurements performed during the 2015 and 2016 data taking periods of the ATLAS detector show that its performance, in terms of stability and noise, fits the specifications. In particular, almost all the PMTs show a voltage instability smaller than 0.5 V corresponding to a gain stability better than 0.5%. A sma…
The ATLAS detector is set to undergo a substantial upgrade termed the "Phase-II" upgrade during the Long-Shutdown in preparation for the start of operation of the High Luminosity Large Hadron Collider (HL-LHC). This paper describes the development and implementation of the Phase-II upgrade low voltage power supply transformer-coupled buck converter (Brick) test bench. A large scale production of approximately 2048 finger low voltage power supplies, with an identical output voltage, is set to be undertaken in the year 2022. This production will culminate in the complete replacement of the LVPS …
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 integrate…
Radiation damage in the plastic scintillator and/or readout WLS fibers in the HE endcap calorimeter 1.4<y<4 in the CMS experiment at LHC and SLHC will require remediation after 2018. We describe one alternative using the existing brass absorber in the Endcap calorimeter, to replace the plastic scintillator tiles with BaF2 tiles, or quartz tiles coated with thin(1-5 micron) films of radiation-hard pTerphenyl(pTP) or the fast phosphor ZnO:Ga. These tiles would be read-out by easily replaceable arrays of straight, parallel WLS fibers coupled to clear plastic-cladded quartz fibers of proven radiat…
The readout systems for the ATLAS silicon trackers and liquid argon calorimeters utilize vertical-cavity surface-emitting laser diodes to communicate between on and off detector readout components. A number of these VCSEL devices have failed well before their expected lifetime. We summarize the failure history and present what has been learned thus far about failure mechanisms and the dependence of the lifetime on environmental conditions.
A highly granular hadronic calorimeter (HCAL) based on scintillator tiles with individual readout by silicon photomultipliers (SiPMs) has been constructed by the CALICE collaboration and has been tested extensively in particle beams at CERN. The 7608 SiPMs coupled to scintillator tiles in the approximately 1 cubic meter large calorimeter allow large sample studies of behavior of these devices under varying voltage and temperature as well as their saturation behavior. We also present detailed studies of the temperature dependence of the calorimeter signal in muon and hadron beams. The calibrati…
