Hadron Calorimeter Research Articles

Upgrade of the ATLAS Tile hadronic calorimeter for high-luminosity LHC run

The ATLAS Tile Calorimeter (TileCal) will undergo a major replacement of its on- and off-detector electronics for the Long Shutdown 3 that is planned for 2024 and 2025. All signals will be digitised and transferred directly to the off-detector electronics, where the signals are reconstructed, stored, and sent to the first level of trigger at a rate of 40MHz. 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 reliability and redundancy of the system. Three different front-end options are presently being investigated for the upgrade and will be chosen after extensive test beam studies. A Hybrid Demonstrator module has been developed. The demonstrator is undergoing extensive testing and is planned for insertion in ATLAS.

CLASSiC: Cherenkov light detection with silicon carbide

We present the CLASSiC R&D for the development of a silicon carbide (SiC) based avalanche photodiode for the detection of Cherenkov light.SiC is a wide-bandgap semiconductor material, which can be used to make photodetectors that are insensitive to visible light. A SiC based light detection device has a peak sensitivity in the deep UV, making it ideal for Cherenkov light. Moreover, the visible blindness allows such a device to disentangle Cherenkov light and scintillation light in all those materials that scintillate above 400nm.Within CLASSiC, we aim at developing a device with single photon sensitivity, having in mind two main applications. One is the use of the SiC APD in a new generation ToF PET scanner concept, using the Cherenov light emitted by the electrons following 511keV gamma ray absorption as a time-stamp. Cherenkov is intrinsically faster than scintillation and could provide an unprecedentedly precise time-stamp. The second application concerns the use of SiC APD in a dual readout crystal based hadronic calorimeter, where the Cherenkov component is used to measure the electromagnetic fraction on an event by event basis.We will report on our progress towards the realization of the SiC APD devices, the strategies that are being pursued toward the realization of these devices and the preliminary results on prototypes in terms of spectral response, quantum efficiency, noise figures and multiplication.

DHCAL with minimal absorber: measurements with positrons

In special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements.

Design of a 56-GJ Twin Solenoid and Dipoles Detector Magnet System for the Future Circular Collider

An aggressive low-mass and high-stress design of a very large detector magnet assembly for the Future Circular Collider (FCC-hh), consisting of a “twin solenoid” and two dipoles, is presented. The twin solenoid features two concentric solenoids. The inner solenoid provides 6 T over a free bore of 12 m and a length of 20 m, enclosing the inner particle trackers and electron and hadron calorimeters. The outer solenoid reduces the stray field of the inner solenoid and provides additional bending power for high-quality muon tracking. Dipoles are included, providing 10 T · m of bending power in a 6-m mean free bore covering the forward directions for η ≥ 2.5 particles. The overall length of this magnet assembly is 43 m. The presence of several separate magnets in the system presents a challenge in terms of forces and torques acting between them. A rigid support structure, part of the cold mass, holds the inner and outer solenoids of the twin solenoid in place. The dipoles are equipped with lateral coils so that the net force and torque are reduced to zero. The second challenge is the substantial conductor and support structure mass used for containing the magnetic pressure. A doped aluminum stabilized and reinforced conductor is proposed, allowing minimal overall mass of the system. The result is a system consisting of a 53-GJ twin solenoid and two 1.5-GJ dipoles. The cold mass and the vacuum vessel mass of the twin solenoid are 3.2 and 2.4 kt, respectively; and the dipole cold mass weighs 0.38 kt. Various properties of the magnet system are discussed such as magnetic, mechanical and thermal properties, quench behavior, and assembly.

Performance of highly granular calorimeters in test beams

The CALICE collaboration has developed highly granular calorimeter prototypes to evaluate technologies for experiments at a future lepton collider optimized for particle flow event reconstruction. These technologies include electromagnetic calorimeters with tungsten absorbers and silicon or scintillator active elements, and hadronic calorimeters with steel and tungsten absorbers with scintillator and GRPC active elements, the former with analog and the latter with purely digital and with semi-digital readout. We will discuss the design and the calibration of the different prototypes. Results on the performance, in particular the energy reconstruction and energy resolution, will be presented. The high granularity of the calorimeters enables reconstruction techniques such as software compensation to improve the energy resolution, which have already been successfully applied to some of the detector prototypes.

First results of the CALICE SDHCAL technological prototype

The CALICE Semi-Digital Hadronic Calorimeter (SDHCAL) prototype, built in 2011, was exposed to beams of hadrons, electrons and muons in two short periods in 2012 on two different beam lines of the CERN SPS. The prototype with its 48 active layers, made of Glass Resistive Plate Chambers and their embedded readout electronics, was run in triggerless and power-pulsing mode. The performance of the SDHCAL during the test beam was found to be very satisfactory with an efficiency exceeding 90% for almost all of the 48 active layers. A linear response (within ± 5%) and a good energy resolution are obtained for a large range of hadronic energies (5–80 GeV) by applying appropriate calibration coefficients to the collected data for both the Digital (Binary) and the Semi-Digital (Multi-threshold) modes of the SDHCAL prototype. The Semi-Digital mode shows better performance at energies exceeding 30 GeV.

Upgrade of the ATLAS Tile Calorimeter Electronics

The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS experiment at LHC. The TileCal readout consists of 9852 channels. The bulk of its upgrade will occur for the High Luminosity LHC phase (Phase II) where the peak luminosity will increase 5× compared to the design luminosity (1034 cm-2s-1) at center of mass energy of 14 TeV. The TileCal upgrade aims at replacing the majority of the on- and off-detector electronics to the extent that all calorimeter signals will be digitized and sent to the off-detector electronics in the counting room. To achieve the required reliability, redundancy has been introduced at different levels. Three different options are presently being investigated for the front-end electronic upgrade. Extensive test beam studies will determine which option will be selected. 10.24 Gbps optical links are used to read out all digitized data to the counting room while 4.8 Gbps down-links are used for synchronization, configuration and detector control. For the off-detector electronics a pre-processor (sROD) is being developed, which takes care of the initial trigger processing while temporarily storing the main data flow in pipeline and de-randomizer memories. Field Programmable Gate Arrays are extensively used for the logic functions off- and on-detector. One demonstrator prototype module with the new calorimeter module electronics, but still compatible with the present system, is planned to be inserted in ATLAS at the end of 2015.

Space-Time Development of Electromagnetic and Hadronic Showers and Perspectives for Novel Calorimetric Techniques

The performance of hadronic calorimeters will be a key parameter at the next generation of High Energy Physics accelerators. A detector combining fine granularity with excellent timing information would prove beneficial for the reconstruction of both jets and electromagnetic particles with high energy resolution. In this work, the space and time structure of high energy showers is studied by means of a Geant 4-based simulation toolkit. In particular, the relevant time scales of the different physics phenomena contributing to the energy loss are investigated. A correlation between the fluctuations of the energy deposition of high energy hadrons and the time development of the showers is observed, which allows for an event-by-event correction to be computed to improve the energy resolution of the calorimeter. These studies are intended to set the basic requirements for the development of a new-concept, total absorption time-imaging calorimeter, which seems now within reach thanks to major technological advancements in the production of fast scintillating materials and compact photodetectors.

Phase I Upgrade of the CMS Hadron Calorimeter

In preparation for Run 2 (2015) and Run 3 of the LHC (2019), the CMS hadron calorimeter has begun a series of ambitious upgrades. These include new photodetectors in addition to improved front-end and back-end readout electronics. In the hadron forward calorimeter, the existing photomultiplier tubes are being replaced with thinner window, multi-anode readout models, while in the central region, the hybrid photodiodes will be replaced with silicon photomultipliers. The front-end electronics will include high precision timing readout, and the back-end electronics will handle the increased data bandwidth. The barrel and endcap longitudinal segmentation will also be increased. This report will describe the motivation for the upgrade, its major components, and its current status.

Upgrade of the Laser calibration system for the ATLAS hadronic calorimeter TileCal

We present in this contribution the new system for Laser calibration of the ATLAS hadronic calorimeter TileCal. The Laser system is a part of the three stage calibration apparatus designed to compute the calibration factors of the individual cells of TileCal. The Laser system is mainly used to correct for short term drifts of the readout of the individual cells. A sub-percent accuracy in the control of the calibration factors is required. To achieve this goal in the LHC Run2 conditions, a new Laser system was designed. The architecture of the system is described with details on the new optical line used to distribute Laser pulses in each individual detector module and on the new electronics used to drive the Laser, to read out optical monitors and to interface the system with the ATLAS readout, trigger and slow control. The LaserII system has been fully integrated into the framework used for measuring calibration factors and for monitoring data quality. First results on the Laser system performances studied are presented.

Hadronic calorimeter shower size: Challenges and opportunities for jet substructure in the superboosted regime

Hadrons have finite interaction size with dense material, a basic feature common to known forms of hadronic calorimeters (HCAL). We argue that substructure variables cannot use HCAL information to access the microscopic nature of jets much narrower than the hadronic shower size, which we call superboosted massive jets. It implies that roughly 15% of their transverse energy profile remains inaccessible due to the presence of long-lived neutral hadrons. This part of the jet substructure is also subject to order-one fluctuations. We demonstrate that the effects of the fluctuations are not reduced when a global correction to jet variables is applied. The above leads to fundamental limitations in the ability to extract intrinsic information from jets in the superboosted regime. The neutral fraction of a jet is correlated with its flavor. This leads to an interesting and possibly useful difference between superboosted W/Z/h/t jets and their corresponding backgrounds. The QCD jets that form the background to the signal superboosted jets might also be qualitatively different in their substructure as their mass might lie at or below the Sudakov mass peak. Finally, we introduce a set of zero-cone longitudinal jet substructure variables and show that while they carry information that might be useful in certain situations, they are not in general sensitive to the jet substructure.

Performance of the prototype readout system for the CMS endcap hadron calorimeter upgrade

The CMS experiment at the CERN Large Hadron Collider (LHC) will upgrade the photon detection and readout systems of its barrel and endcap hadron calorimeters (HCAL) through the second long shutdown of the LHC in 2018. The upgrade includes new silicon photomultipliers (SiPMs), SiPM control electronics, signal digitization via the Fermilab QIE11 ASIC, data formatting and serialization via a Microsemi FPGA, and data transmission via CERN Versatile Link technology. The first prototype system for the endcap HCAL has been assembled and characterized on the bench and in a test beam. The design of this new system and prototype performance are described.

First large volume characterization of the QIE10/11 custom front-end integrated circuits

The CMS experiment at the CERN Large Hadron Collider (LHC) will upgrade the photon detection and readout systems of its barrel and endcap hadron calorimeters (HCAL) through the second long shutdown of the LHC in 2018. A central feature of this upgrade is the development of two new versions of the QIE (Charge Integrator and Encoder), a Fermilab-designed custom ASIC for measurement of charge from detectors in high-rate environments. These most recent additions to the QIE family feature 17-bits of dynamic range with 1% digitization precision for high charge and a time-to-digital converter (TDC) with half nanosecond resolution all with 16 bits of readout per bunch crossing. For the first time, the CMS experiment has produced and characterized in great detail a large volume of chips. The characteristics and performance of the new QIE and their related chip-to-chip variations as measured in a sample of 10,000 chips is described.

The CMS Beam Halo Monitor electronics

The CMS Beam Halo Monitor has been successfully installed in the CMS cavern in LHC Long Shutdown 1 for measuring the machine induced background for LHC Run II. The system is based on 40 detector units composed of synthetic quartz Cherenkov radiators coupled to fast photomultiplier tubes (PMTs). The readout electronics chain uses many components developed for the Phase 1 upgrade to the CMS Hadronic Calorimeter electronics, with dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal is digitized by a charge integrating ASIC (QIE10), providing both the signal rise time, with few nanosecond resolution, and the charge integrated over one bunch crossing. The backend electronics uses microTCA technology and receives data via a high-speed 5 Gbps asynchronous link. It records histograms with sub-bunch crossing timing resolution and is read out via IPbus using the newly designed CMS data acquisition for non-event based data. The data is processed in real time and published to CMS and the LHC, providing online feedback on the beam quality. A dedicated calibration monitoring system has been designed to generate short triggered pulses of light to monitor the efficiency of the system. The electronics has been in operation since the first LHC beams of Run II and has served as the first demonstration of the new QIE10, Microsemi Igloo2 FPGA and high-speed 5 Gbps link with LHC data.

Highly granular hadron calorimeter: software compensation and shower decomposition

The highly granular analogue hadron calorimeter was developed and constructed by the CALICE collaboration. The active layers of the calorimeter are assembled from scintillator tiles with individual readout by silicon photomultipliers and are interleaved with absorber plates. The response and resolution of the calorimeter equipped with steel absorber was intensively tested in single particle beams. The application of software compensation techniques developed for the scintillator-steel prototype allows for reduction of the stochastic term of the single particle resolution from 58%/ √E/GeV to 45%/ √E/GeV. The detailed study and decomposition of the longitudinal and radial profiles of hadron-induced showers in the energy range from 10 to 80 GeV are presented and compared to GEANT4 simulations.

A radiation tolerant Data link board for the ATLAS Tile Cal upgrade

This paper describes the latest, full-functionality revision of the high-speed data link board developed for the Phase-2 upgrade of ATLAS hadronic Tile Calorimeter. The link board design is highly redundant, with digital functionality implemented in two Xilinx Kintex-7 FPGAs, and two Molex QSFP+ electro-optic modules with uplinks run at 10 Gbps. The FPGAs are remotely configured through two radiation-hard CERN GBTx deserialisers (GBTx), which also provide the LHC-synchronous system clock. The redundant design eliminates virtually all single-point error modes, and a combination of triple-mode redundancy (TMR), internal and external scrubbing will provide adequate protection against radiation-induced errors. The small portion of the FPGA design that cannot be protected by TMR will be the dominant source of radiation-induced errors, even if that area is small.

Radiation hardness of semiconductor avalanche detectors for calorimeters in future HEP experiments

During the last years, semiconductor avalanche detectors are being widely used as the replacement of classical PMTs in calorimeters for many HEP experiments. In this report, basic selection criteria for replacement of PMTs by solid state devices and specific problems in the investigation of detectors radiation hardness are discussed. The design and performance of the hadron calorimeters developed for the future high energy nuclear physics experiments at FAIR, NICA, and CERN are discussed. The Projectile Spectator Detector (PSD) for the CBM experiment at the future FAIR facility, the Forward Calorimeter for the NA61 experiment at CERN and the Multi Purpose Detector at the future NICA facility are reviewed. Moreover, new methods of data analysis and results interpretation for radiation experiments are described. Specific problems of development of detectors control systems and possibilities of reliability improvement of multi-channel detectors systems are shortly overviewed. All experimental material is based on the investigation of SiPM and MPPC at the neutron source in NPI Rez.

Shower development of particles with momenta from 15 GeV to 150 GeV in the CALICE scintillator-tungsten hadronic calorimeter

We present a study of showers initiated by electrons, pions, kaons, and protons with momenta from 15 GeV to 150 GeV in the highly granular CALICE scintillator-tungsten analogue hadronic calorimeter. The data were recorded at the CERN Super Proton Synchrotron in 2011. The analysis includes measurements of the calorimeter response to each particle type as well as measurements of the energy resolution and studies of the longitudinal and radial shower development for selected particles. The results are compared to Geant4 simulations (version 9.6.p02). In the study of the energy resolution we include previously published data with beam momenta from 1 GeV to 10 GeV recorded at the CERN Proton Synchrotron in 2010.

Energy reconstruction in a highly granularity semi-digital hadronic calorimeter

The Semi-Digital Hadronic CALorimeter(SDHCAL) using Glass Resistive Plate Chambers (GRPCs) is one of the calorimeters proposed for particle physics experiments at the future electron-positron collider. It is a high granularity calorimeter which is required for the application of the particle flow algorithm in order to improve the jet energy resolution as one of the goals of this experiments. We discuss the energy reconstruction, based on digital and semi-Digital methods, to study the effect on the improvement of the single particle energy resolution and the linearity of the detecor response. This study was performed with the GEANT4 simulation. Results on the energy resolution and linearity, for negative pions over an energy range from 1 to 100 GeV are presented and compared with different energy reconstruction methods including Artificial Neural Networks.

Calibration and data quality systems of the ATLAS Tile Calorimeter during the LHC Run-I operations

The Tile Calorimeter is the hadronic calorimeter covering the central region of the ATLAS detector at the LHC. It consists of thin steel plates and scintillating tiles. Wavelength shifting fibers coupled to the tiles collect the produced light and are read out by photomultiplier tubes. The calibration scheme of the Tile Calorimeter comprises Cs radioactive source, laser and charge injection systems. Each stage of the signal production of the calorimeter from scintillation light to digitization is monitored and equalized. Description of the different TileCal calibration systems as well as the results on their performance in terms of calibration factors, linearity and stability is given. The data quality procedures and efficiency of the Tile Calorimeter during the LHC Run-1 data-taking period are presented as well.