3,932 research outputs found
Study of TileCal Sampling Fraction for Improvement of Monte-Carlo Data Reconstruction
In this work we made a detailed calculation of Tile Calorimeter Sampling Fraction parameter (TSF) using single electron and pion Geant4 Monte-Carlo simulation of ATLAS hadronic calorimeter (TileCal) within ATHENA --- common software framework of ATLAS. Our study was based on MC Truth data provided by special Geant4 MC simulation objects --- Calibration Hits, design which was implemented in TileCal simulation by our group. We used this TSF value for reconstruction of TileCal single pions simulation data. It was done for ATLAS Combined test beam 2004 (CTB2004) configuration setup. Results of the reconstruction were compared with MC Truth and CTB2004 reconstructed experimental data. Good agreement between them shows quite evident improvement in TileCal MC data reconstruction of hadronic shower energy in electromagnetic scale
Artificial Neural Networks for reconstruction of energy losses in dead materials between barrel LAr and Tile calorimeters: exploration and results
In the course of computational experiments with Monte-Carlo events for ATLAS Combined Test Beam 2004 setup Artificial Neural Networks (ANN) technique was applied for reconstruction of energy losses in dead materials between barrel LAr and Tile calorimeters (Edm). The constructed ANN procedures exploit as their input vectors the information content of different sets of variables (parameters) which describe particular features of the hadronic shower of an event in ATLAS calorimeters. It was shown that application of ANN procedures allows one to reach 40% reduction of the Edm reconstruction error compared to the conventional procedure used in ATLAS collaboration. Impact of various features of a shower on the precision of reconstruction is presented in detail. It was found that longitudinal shower profile information brings greater improvement in reconstruction accuracy than cell energies information in LAr3 and Tile1 samplings
Study of the Transition Effect with the ATLAS Tile Calorimeter
With the aim to establish the electromagnetic energy scale of the ATLAS Tile calorimeter and understanding the performance of the calorimeter to electrons 12% of modules have been exposed in electron beams with various energies. On a basis of the obtained electromagnetic calibration constants we have determined the e/mip values in dependence of the absorber thickness using different beam incident angles. We have observed the transition effect (e/mip < 1) and, for the first time, its behaviour as a function of the absorber thickness --- the e/mip ratio decreases logarithmically when the absorber thickness increases this is well described by the GEANT4 version 6.2 Monte Carlo simulation. These results are important for precision electromagnetic energy scale determination for the ATLAS Tile calorimeter
Electromagnetic Cell Level Calibration for ATLAS Tile Calorimeter Modules
We have determined the electromagnetic calibration constants of 11% TileCal modules exposed to electron beams with incident angles of 20 and 90 degrees. The gain of all the calorimeter cells have been pre-equalized using the radioactive Cs-source that will be also used in situ. The average values for these modules are equal to: for the flat filter method 1.154+/-0.002 pC/GeV and 1.192+/-0.002 pC/GeV for 20 and 90 degrees, for the fit method 1.040+/-0.002 pC/GeV and 1.068+/-0.003 pC/GeV, respectively. These average values for all cells of calibrated modules agree with the weighted average calibration constants for separate modules within the errors. Using the individual calibration constants for every module the RMS spread value of constants will be 1.9+/-0.1 %. In the case of the global constant this value will be 2.6+/-0.1 %. Finally, we present the global constants which should be used for the electromagnetic calibration of the ATLAS Tile hadronic calorimeter data in the ATHENA framework. These constants are equal to 1.15 pC/GeV in the case of the flat filter method and 1.04 pC/GeV for the fit one
Disappearance of Elliptic Flow: A New Probe for the Nuclear Equation of State
Using a relativistic hadron transport model, we investigate the utility of
the elliptic flow excitation function as a probe for the stiffness of nuclear
matter and for the onset of a possible quark-gluon-plasma (QGP)
phase-transition at AGS energies 1 < E_Beam < 11 AGeV. The excitation function
shows a strong dependence on the nuclear equation of state, and exhibits
characteristic signatures which could signal the onset of a phase transition to
the QGP.Comment: 11 pages, 4 Postscript figures, uses epsf.sty, submitted to Physical
Review Letter
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