The central hadron calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC) is readout by about 10,000 photomultipliers (PMTs). Earlier studies of performance showed a degradation in ...PMT response as a function of the integrated anode charge. A model of the time evolution of the PMT response was made, with a projected loss exceeding 25% for the fraction of the PMTs (about 8% of the total) that will integrate an anode charge of 600 C, expected at the end of the High-Luminosity LHC program. These PMTs will be replaced with a newer version, in order to keep the global detector performance at an optimal level. A local test setup is being used in the Pisa laboratory to study the long term response of a new PMT model considered for replacement in the hadron calorimeter readout of most active cells. For the first time this new PMT model has been tested after integrating more than 250 C of anode charge. Preliminary results obtained from data collected in the Pisa laboratory are shown.
Hadron detection with a dual-readout fiber calorimeter Lee, S.; Cardini, A.; Cascella, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2017, Volume:
866, Issue:
C
Journal Article
Peer reviewed
Open access
In this paper, we describe measurements of the response functions of a fiber-based dual-readout calorimeter for pions, protons and multiparticle “jets” with energies in the range from 20 to 180 GeV. ...The calorimeter uses lead as absorber material and has a total mass of 1350 kg. It is complemented by leakage counters made of scintillating plastic, with a total mass of 500 kg. The effects of these leakage counters on the calorimeter performance are studied as well. In a separate section, we investigate and compare different methods to measure the energy resolution of a calorimeter. Using only the signals provided by the calorimeter, we demonstrate that our dual-readout calorimeter, calibrated with electrons, is able to reconstruct the energy of proton and pion beam particles to within a few percent at all energies. The fractional widths of the signal distributions for these particles (σ∕E) scale with the beam energy as 30%∕E, without any additional contributing terms.
The electromagnetic performance of the RD52 fiber calorimeter Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2014, Volume:
735
Journal Article
Peer reviewed
Open access
The RD52 calorimeter is an instrument intended to detect both electromagnetic and hadronic showers, as well as muons, using the dual-readout principle. Scintillation and Cherenkov light provide the ...two signals which, in combination, allow for superior hadronic performance. In this paper, we report on the electromagnetic performance of this instrument, and compare this performance with that of other calorimeters that were constructed with similar goals in mind.
The RD52 dual-readout calorimeter is a longitudinally unsegmented instrument intended for the detection of both electromagnetically and hadronically interacting particles with unprecedented ...precision. In this paper, the identification of the showering particles and, in particular, the identification of electrons and gamma s with this instrument are investigated. The techniques used for this purpose include differences in the shower development observed with scintillation light and Cherenkov radiation, the radial shower profile of the particles and the time structure (including the starting point) of the calorimeter signals. It turns out that, at 60 GeV, electrons can be correctly identified in 99.8% of the cases, by means of criteria that eliminate 99.8% of the hadrons.
The small-angle performance of a dual-readout fiber calorimeter Cardini, A.; Cascella, M.; Choi, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2016, Volume:
808, Issue:
C
Journal Article
Peer reviewed
Open access
The performance of the RD52 dual-readout calorimeter is measured for very small angles of incidence between the 20GeV electron beam particles and the direction of the fibers that form the active ...elements of this calorimeter. The calorimeter response is observed to be independent of the angle of incidence for both the scintillating and the Čerenkov fibers, whereas significant differences are found between the angular dependence of the energy resolution measured with these two types of fibers. The experimental results are on crucial points at variance with the predictions of GEANT4 Monte Carlo simulations.
A comparison of BGO and BSO crystals used in the dual-readout mode Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2011, Volume:
640, Issue:
1
Journal Article
Peer reviewed
We report on a systematic study of the properties of two high-
Z scintillating crystals, bismuth germanate (BGO) and bismuth silicate (BSO), in view of the possible application of such crystals in ...dual-readout calorimeters. Whereas the light attenuation characteristics of both crystals are about the same, BSO offers a considerably higher Cherenkov light yield, and with a given UV filter the separation between the Cherenkov and scintillation signals is substantially better in this crystal.
The RD52 calorimeter uses the dual-readout principle to detect both electromagnetic and hadronic showers, as well as muons. Scintillation and Cherenkov light provide the two signals which, in ...combination, allow for superior hadronic performance. In this paper, we report on detailed, GEANT4 based Monte Carlo simulations of the performance of this instrument. The results of these simulations are compared in great detail to measurements that have been carried out and published by the DREAM Collaboration. This comparison makes it possible to understand subtle details of the shower development in this unusual particle detector. It also allows for predictions of the improvement in the performance that may be expected for larger detectors of this type. These studies also revealed some inadequacies in the GEANT4 simulation packages, especially for hadronic showers, but also for the Cherenkov signals from electromagnetic showers.
Detection of electron showers in dual-readout crystal calorimeters Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2012, Volume:
686
Journal Article
Peer reviewed
Some high-Z scintillating crystals offer the possibility to distinguish the contributions from the scintillation and Čherenkov mechanisms to the generated signals. Among these crystals are BGO and ...PbWO4. We have tested matrices of these crystals as electromagnetic calorimeters and studied the properties of the Čherenkov and scintillation components of the signals generated by high-energy electrons showering in these detectors.
New crystals for dual-readout calorimetry Akchurin, N.; Bedeschi, F.; Cardini, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2009, Volume:
604, Issue:
3
Journal Article
Peer reviewed
Open access
Lead tungstate crystals doped with small fractions of praesodynium or molybdenum have been tested in beams of high-energy electrons. The goal of these tests was to study the effects of such dopants ...on the capability to separate the signal components deriving from the Cherenkov and scintillation light generated by the beam particles. These studies were carried out in view of the possible application of such crystals in dual-readout calorimeters.
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