Hadron Calorimeter Research Articles

T3B — an experiment to measure the time structure of hadronic showers

The goal of the T3B experiment is the measurement of the time structure of hadronic showers with nanosecond precision and high spatial resolution together with the CALICE hadron calorimeter prototypes, with a focus on the use of tungsten as absorber medium. The detector consists of a strip of 15 scintillator cells individually read out by silicon photomultipliers (SiPMs) and fast oscilloscopes with a PC-controlled data acquisition system. The data reconstruction uses an iterative subtraction technique which provides a determination of the arrival time of each photon on the light sensor with sub-nanosecond precision. The calibration is based on single photon-equivalent dark pulses constantly recorded during data taking, automatically eliminating the temperature dependence of the SiPM gain. In addition, a statistical correction for SiPM afterpulsing is demonstrated. To provide the tools for a comparison of T3B data with GEANT4 simulations, a digitization routine, which accounts for the detector response to energy deposits in the detector, has been implemented.

Track segments in hadronic showers in a highly granular scintillator-steel hadron calorimeter

We investigate the three dimensional substructure of hadronic showers in the CALICE scintillator-steel hadronic calorimeter. The high granularity of the detector is used to find track segments of minimum ionising particles within hadronic showers, providing sensitivity to the spatial structure and the details of secondary particle production in hadronic cascades. The multiplicity, length and angular distribution of identified track segments are compared to GEANT4 simulations with several different shower models. Track segments also provide the possibility for in-situ calibration of highly granular calorimeters.

Validation of GEANT4 Monte Carlo models with a highly granular scintillator-steel hadron calorimeter

Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8 GeV to 100 GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated.

Imaging hadron calorimetry for future Lepton Colliders

To fully exploit the physics potential of a future Lepton Collider requires detectors with unprecedented jet energy and dijet-mass resolution. To meet these challenges, detectors optimized for the application of Particle Flow Algorithms (PFAs) are being designed and developed. The application of PFAs, in turn, requires calorimeters with very fine segmentation of the readout, so-called imaging calorimeters.This talk reviews progress in imaging hadron calorimetry as it is being developed for implementation in a detector at a future Lepton Collider. Recent results from the large prototypes built by the CALICE Collaboration, such as the Scintillator Analog Hadron Calorimeter (AHCAL) and the Digital Hadron Calorimeters (DHCAL and SDHCAL) are being presented. In addition, various R&D efforts beyond the present prototypes are being discussed.

STAR Upgrade Plan for the Coming Decade

The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. STAR has also embarked on an upgrade plan to extend the capabilities for measuring jets, electron/photon and leading particles in the forward rapidity region in the coming decade. Planned detector upgrades include tracking detectors for charged particles, electro-magnetic and hadronic calorimeters and particle identification detector in the forward direction. We will present physics motivations, status of detector R&D and design considerations for the forward measurements focusing on p + p/p + A and polarized p + p collisions.

Performance study of a single layer THGEM detector at E3 line of Beijing Test Beam Facility

A single layer THick Gaseous Electron Multiplier (THGEM) detector has been studied at E3 line of Beijing Test Beam Facility (BTBF). The responses of the detector to p and π+ at momenta 400MeV/c, 500MeV/c, 600MeV/c and 700MeV/c were investigated at different detector drift distances: 5mm and 3mm, the working gas was Neon/CH4 (95/5). The p/π+ particles were identified through Time of Flight (TOF) method using plastic scintillation detectors. Energy spectra of different particles at various momenta were studied, and they were compared with Geant4 simulation results. Detection efficiencies for p were measured to be about 97% for 5mm drift distance, and 91% for 3mm. Detection efficiencies for π+ were lower, in the range of 84%–92%. Based on the beam test results, the THGEM detector showed performances satisfying the requirements of a Digital Hadron CALorimeters (DHCAL) in future experiments.

Jet Measurements in Heavy Ion Collisions with an Upgraded PHENIX Detector

The PHENIX Collaboration is pursuing an upgrade to the PHENIX detector to enable investigations of specific, outstanding questions that will advance our understanding of the strongly coupled quark-gluon plasma (sQGP). The greatly upgraded detector, called sPHENIX, consists of a superconducting solenoid and electromagnetic and hadronic calorimeters with a fiducial acceptance of and |η| < 1 around an existing silicon tracking detector, the VTX. It will have excellent capabilities for measuring an important set of jet observables. These measurements, in conjunction with similar measurements at the LHC, will provide information about energy loss, transport coefficients, and the fundamental constituents of the sQGP in the domain of strongest coupling, near Tc.

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.

Performances of the signal reconstruction in the ATLAS Hadronic Tile Calorimeter

The Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of ATLAS. It is a key detector for the reconstruction of hadrons, jets, tau leptons and missing transverse energy. TileCal is a sampling calorimeter using steel as an absorber and plastic scintillators as an active medium. The scintillators are read-out by wavelength shifting fibers coupled to photomultiplier tubes (PMTs). The analogue signals from the PMTs are amplified, shaped and digitized by sampling the signal every 25ns. The read-out system is designed to reconstruct the data in real time fulfilling the tight time constraint imposed by the ATLAS first level trigger rate (100kHz). The signal amplitude and phases for each channel are measured using Optimal Filtering algorithms both at online and offline level. We present the performances of these techniques on the data collected in the proton–proton collisions at center-of-mass energy of 7TeV. We show in particular the measurements of low amplitudes, close to the pedestal value, using as probe high transverse momenta muons produced in the proton–proton collisions.

English

By using the tungsten as passive element and the Glass Resistive Plate Chambers (GRPCs) as active element, the gaseous hadronic calorimeter is studied as a possible detector for the future International Linear Collider (ILC). The results of the numerical study, using the GEANT4 simulation package, of the performance of this calorimeter when it is exposed to a negative pion beam in an energy range from 5 GeV to 100 GeV are presented in this paper. Operating characteristics of this prototype, such as signal linearity, energy resolution and reconstructed energy have been simulated and examined. Moreover, a comparison between the Digital Hadron Calorimeter (DHCAL) and the Analog Hadron Calorimeter (AHCAL) is made. &nbsp; Key words:&nbsp;Calorimetry, resistive plate chambers, international linear collider (ILC), GEANT4.

A systematic study of the hybrid experiment at Mt.Chacaltaya

In the hybrid experiment on Mt.Chacaltaya, we can observe three di erent components of air- showers, that is, air-shower size, burst-density and high energy families (a bundle of high energy particles). Burst-density in each block of hadron calorimeters are newly recalculated in simulations in oder to compare directly to the experimental data. Energy deposits in the scintillators of the hadron calorimeters are calculated using GEANT4 for every particle, incident upon the hadron calorimeter, in the air-showers simulated using CORSIKA, and are converted into burst-density, taking into consideration the exact structure of experimental hadron calorimeter. We study correlations among three observable components in the air-showers. Correlations between air-shower size and burst-density and those between air-shower size and accompanied family energy can be explained by model calculations by adjusting primary particle composition, the former correlation is in favor of proton-primaries but the latter iron-primaries. No model can describe well observed correlations between burst-density and family energy. That is, the observed family energy accompanied by the air-showers with larger burst-density is systematically smaller than that expected in the simulated events. E ects of a fluc- tuation in the cross-section of hadronic interactions are studied to settle the disagreement between experimental data and simulations.

A systematic study of the hybrid experiment at Mt.Chacaltaya

In the hybrid experiment on Mt.Chacaltaya, we can observe three different components of airshowers, that is, air-shower size, burst-density and high energy families (a bundle of high energy particles). Burst-density in each block of hadron calorimeters are newly recalculated in simulations in oder to compare directly to the experimental data. Energy deposits in the scintillators of the hadron calorimeters are calculated using GEANT4 for every particle, incident upon the hadron calorimeter, in the air-showers simulated using CORSIKA, and are converted into burst-density, taking into consideration the exact structure of experimental hadron calorimeter. We study correlations among three observable components in the air-showers. Correlations between air-shower size and burst-density and those between air-shower size and accompanied family energy can be explained by model calculations by adjusting primary particle composition, the former correlation is in favor of proton-primaries but the latter iron-primaries. No model can describe well observed correlations between burst-density and family energy. That is, the observed family energy accompanied by the air-showers with larger burst-density is systematically smaller than that expected in the simulated events. Effects of a fluctuation in the cross-section of hadronic interactions are studied to settle the disagreement between experimental data and simulations.

The optical instrumentation of the ATLAS Tile Calorimeter

The Tile Calorimeter, covering the central region of theATLAS experiment up to pseudorapidities of ±1.7, is a sampling devicebuilt with scintillating tiles that alternate with iron plates. The light iscollected in wave-length shifting (WLS) fibers and is read out withphotomultipliers. In the characteristic geometry of this calorimeter thetiles lie in planes perpendicular to the beams, resulting in a very simpleand modular mechanical and optical layout. This paper focuses on theprocedures applied in the optical instrumentation of the calorimeter, whichinvolved the assembly of about 460,000 scintillator tiles and 550,000 WLSfibers. The outcome is a hadronic calorimeter that meets the ATLASperformance requirements, as shown in this paper.

Simulations and Measurements for a concept of powering CALICE-AHCAL at a train-cycled accelerator

Improving calorimetry by usage of the particle-flow algorithm requires to record the details of the shower development. Therefore a high granularity analogue readout hadron calorimeter (AHCAL) with small sensors and with electronics handling the enormous amount of channels, ≈ 40 000/m3, is required. Homogeneity is maintained by avoiding cooling tubes in the active volume and only cooling at the service end.For this concept low power consumption per channel, 40 μW, is essential. Future linear e+e−− collider designs, ILC or CLIC, foresee duty cycles for the bunch delivery. At ILC bunch trains of 1 ms duration are followed by long breaks of 200 ms. Power cycling the front end electronics with the train structure can reduce power consumption by a factor 100. However for a full scale CALICE-AHCAL switched currents reach magnitudes of kilo-amperes.This paper describes the design chain from front end PCB's through to external power supplies. By simulations a concept is developed, in which effects of electromagnetic interferences are kept small and localized. The goal is to keep current loops small, to limit the switched current to the region near the switched consumer and to allow only small frequency currents to spread out further into the system. By that analogue performance can be kept high and parasitic couplings to the surrounding metal structures and other sub-detectors will be minimized. Measurements with existing prototypes support the validity of the simulations.

Nuclear-nuclear collision centrality determination by the spectators calorimeter for the MPD setup at the NICA facility

The work conditions of the hadron calorimeter for spectators registration (Zero Degree Calorimeter, ZDC) were studied for the heavy nuclei collisions with the several GeV invariant energy. The ZDC simulations were performed for the MPD (Multi-Purpose Detector) at the NICA (Nuclotron-based Ion Collider fAcility) collider, which are under developement at the Joint Institute for Nuclear Research (JINR, Dubna). Taking into account the spectator nuclear fragments leads to a nonmonotonic dependence of the ZDC response on the impact parameter. The reason for this dependence studied with several event generators is the primary beam hole in the ZDC center. It is shown, that the ZDC signal should be combined with a data from other MPD@NICA detector subsystems to determine centrality.

Tau Reconstruction, Identification Algorithms and Performance in ATLAS

Tau leptons play an important role in the physics program at the LHC. They are used not only in searches for new phenomena like the Higgs boson or Supersymmetry and electroweak measurements but also in detector related studies like the determination of the missing transverse energy scale. Optimal identification of hadronically decaying tau leptons is achieved by using detailed information from tracking and calorimeter detector components. Variables describing the properties of calorimeter energy deposits and track reconstruction within tau candidates are combined in multi–variate discriminants, to achieve high rejection against backgrounds, which is challenging in a high particle density environments. The identification efficiencies are measured in W→τν and Z→ττ events, and compared with the prediction of the Monte Carlo simulation. The energy scale uncertainties for tau leptons are determined by investigating single hadron calorimeter response, as well as kinematic distributions in Z→ττ events.

New results from the NA49 experiment on hadron production in p+p and p+C interactions and survey of backward hadrons in p+C collisions

Recent results on proton, anti-proton, neutron and charged kaon production in proton-proton and proton, anti-proton, neutron, deuteron and triton production in proton-carbon collisions at 158 GeV/c beam momentum are presented. Data samples of 4.8 million and 385 734 inelastic events in p+p and p+C, respectively, are obtained with the NA49 detector at the CERN SPS accelerator. The charged particles are identified by energy loss measurement in a system of four TPC chambers, while the neutrons are detected in a forward hadronic calorimeter. The data cover a major fraction of the phase space, ranging from 0 to 1.9 GeV in pT and in Feynman x variable from -0.8 to 0.95 for protons, from -0.2 to 0.3 for anti-protons, from 0.1 to 0.95 for neutrons and from 0 to 0.5 for kaons. The comparison of the results on proton and neutron production in p+p interactions and deep inelastic e+p collisions at HERA reveals an independence of target fragmentation on the projectile type. Using the charged kaon data in p+p collisions as a reference, a new evaluation of the energy dependence of kaon production, including neutral kaons, is conducted over a range from 3 GeV to p+p− collider energies. A survey of backward production of protons and pions in p+C collisions in the range of lab angles from 10 to 180 degrees, from 0.2 to 1.2 GeV/c in lab momentum and from 1 to 400 GeV/c in projectile momentum has been performed.

The ATLAS Tile Calorimeter Calibration and Performance

A brief summary of the hadronic calorimeter calibration systems and performance results, in the ATLAS detector at the LHC is given.

Performance of the ATLAS Tile Calorimeter

The Tile Calorimeter is the central section of the ATLAS hadronic calorimeter at the Large Hadron Collider. It is a key detector for the measurement of hadrons, jets, tau leptons and missing transverse energy. Because of its very good signal to noise ratio it is also useful for the identification and reconstruction of muons. The calibration and performance of the calorimeter have been established through test beam measurements, cosmic ray muons and the large sample of pp collisions. Results on the calorimeter performance are presented, including the absolute energy scale, time resolution, and associated stabilities.

SPIROC: design and performances of a dedicated very front-end electronics for an ILC Analog Hadronic CALorimeter (AHCAL) prototype with SiPM read-out

For the future e+ e- International Linear Collider (ILC) the ASIC SPIROC (Silicon Photomultiplier Integrated Read-Out Chip) was designed to read out the Analog Hadronic Calorimeter (AHCAL) equipped with Silicon Photomultiplier (SiPM). It is an evolution of the FLC_SiPM chip designed by the OMEGA group in 2005. SPIROC2 [1] was realized in AMS SiGe 0.35 μm technology [2] and developed to match the requirements of large dynamic range, low noise, low consumption, high precision and large number of read-out channels. This ASIC is a very front-end read-out chip that integrates 36 self triggered channels with variable gain to achieve charge and time measurements. The charge measurement must be performed from 1 up to 2000 photo-electrons (p.e.) corresponding to 160 fC up to 320 pC for SiPM gain 106. The time measurement is performed with a coarse 12-bit counter related to the bunch crossing clock (up to 5 MHz) and a fine time ramp based on this clock (down to 200 ns) to achieve a resolution of 1 ns. An analog memory array with a depth of 16 for each channel is used to store the time information and the charge measurement. The analog memory content (time and charge) is digitized thanks to an internal 12-bit Wilkinson ADC. The data is then stored in a 4kbytes RAM. A complex digital part is necessary to manage all these features and to transfer the data to the DAQ. SPIROC2 is the second generation of the SPIROC ASIC family designed in 2008 by the OMEGA group. A very similar version (SPIROC2c) was submitted in February 2012 to improve the noise performance and also to integrate a new TDC (Time to Digital Converter) structure. This paper describes SPIROC2 and SPIROC2c ASICs and illustrates the main characteristics thank to a series of measurements.