The ATLAS experiment is designed to study the proton-proton collisions produced at the Large Hadron Collider (LHC) at CERN. The electromagnetic calorimeters use lead as passive material and are ...characterized by an accordion geometry that allows a fast and uniform azimuthal response. Copper and tungsten were chosen as passive material for the hadronic calorimetry; whereas a parallel plate geometry was adopted at large polar angles, an innovative one based on cylindrical electrodes with thin argon gaps was designed for the coverage at low angles, where the particles flow is higher. The performance of these new calorimeters is being studied in highest intensity particle beams. This contribution covers all aspects of the first three years of operation. The excellent performance achieved is especially detailed in the context of the discovery of the Higgs boson announced in July 2012. The future plans to preserve this performance until the end of the LHC program are also presented.
We evaluate the validity of the GEANT4 electromagnetic and hadronic physics models by comparing experimental data from beam tests of modules of the ATLAS hadronic end-cap calorimeter with ...GEANT4-based simulations. Two physics lists (LHEP and QGSP) for the simulation of hadronic showers are evaluated. Calorimeter performance parameters like the energy resolution and shapes of showers are studied both for electrons and charged pions. Furthermore, throughout the paper we compare GEANT4 and the corresponding predictions of GEANT3 used with the G-CALOR code for hadronic shower development.
The validation of GEANT4 physics models is done by comparing experimental data from beam tests of modules of the ATLAS hadronic end-cap calorimeter with GEANT4 based simulations. Various physics ...lists for the simulation of hadronic showers are evaluated. We present results of studies of the calorimeter performance parameters (like energy resolution and shower shapes) as well as results of investigations of the influence of the Birks' law and of cuts on the time of development of hadronic showers.
This paper describes the on-detector electronics of the ATLAS hadronic end-cap calorimeter (HEC). The electronics is operated in liquid argon; therefore attention is paid to its performance at low ...temperatures. The core of the electronics are Gallium Arsenide (GaAs) preamplifiers. We present design, layout and results of various tests of the preamplifier chips and summing boards. The calibration and signal cables have been studied under laboratory conditions and the signal distortion is modeled. All parts of the electronics have been produced, tested and assembled on the calorimeter modules. The summary of the commissioning tests is presented.
The ATLAS detector has been designed for operation at the Large Hadron Collider at CERN. ATLAS includes electromagnetic and hadronic liquid argon calorimeters, with almost 200,000 channels of data ...that must be sampled at the LHC bunch crossing frequency of 40 MHz. The calorimeter electronics calibration and readout are performed by custom electronics developed specifically for these purposes. This paper describes the system performance of the ATLAS liquid argon calibration and readout electronics, including noise, energy and time resolution, and long term stability, with data taken mainly from full-system calibration runs performed after installation of the system in the ATLAS detector hall at CERN.
Liquid argon calorimeter performance at high rates Glatte, A.; Kobel, M.; Mader, W.F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2012, Letnik:
669
Journal Article
Recenzirano
We project the performance of the ATLAS liquid argon endcap and forward calorimeters at the planned high luminosity LHC option HL-LHC by exposing small calorimeter modules of the electromagnetic, ...hadronic, and forward calorimeters to high intensity beams at IHEP/Protvino. The beam intensity extends well beyond the maximum expected for these calorimeters at HL-LHC. The signal reconstruction and calorimeter performance have been studied in full detail.
The local hadronic calibration scheme developed for the reconstruction and calibration of jets and missing transverse energy in ATLAS has been evaluated using data obtained during combined beam tests ...of modules of the ATLAS liquid argon endcap and forward calorimeters. These tests covered the pseudorapidity range of 2.5 < | ? | < 4.0 . The analysis has been performed using special sets of calibration weights and corrections obtained with the Geant4 simulation of a detailed beam-test setup. The evaluation itself has been performed through the careful study of specific calorimeter performance parameters such as e.g. energy response and resolution, shower shapes, as well as different physics lists of the Geant4 simulation.
After two decades of a development of the unitary and analytic models of the
electromagnetic structure of hadrons and nuclei their main principles are
briefly formulated, then a general scheme of ...their applications to the
electromagnetic, weak and strong interaction processes are traced out and
finally, some results of their successful applications are reviewed.
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