ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2012). Measurement of the b-hadron production cross section using decays to D*(+)mu X- final states in pp collisions at root s=7 TeV with the ATLAS detector. Nucl. Phys. B, 864(3), 341–381.
Abstract: The b-hadron production cross section is measured with the ATLAS detector in pp collisions at root s = 7 TeV, using 3.3 pb(-1) of integrated luminosity, collected during the 2010 LHC run. The b-hadrons are selected by partially reconstructing D*(+)mu X- final states. Differential cross sections are measured as functions of the transverse momentum and pseudorapidity. The measured production cross section for a b-hadron with p(T) > 9 GeV and vertical bar eta vertical bar < 2.5 is 32.7 +/- 0.8(stat.)(-6.8)(+4.5)(syst.) μb, higher than the next-to-leading-order QCD predictions but consistent within the experimental and theoretical uncertainties.
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ATLAS Collaboration(Abat, E. et al), Bernabeu Verdu, J., Castillo Gimenez, V., Costa, M. J., Escobar, C., Ferrer, A., et al. (2011). A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test. J. Instrum., 6, P06001–35pp.
Abstract: A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20 GeV and 180 GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.
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ATLAS Collaboration(Abat, E. et al), Castillo Gimenez, V., Ferrer, A., Gonzalez, V., Higon-Rodriguez, E., Mitsou, V. A., et al. (2010). Study of energy response and resolution of the ATLAS barrel calorimeter to hadrons of energies from 20 to 350 GeV. Nucl. Instrum. Methods Phys. Res. A, 621(1-3), 134–150.
Abstract: A fully instrumented slice of the ATLAS detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. In this paper, the results of the measurements of the response of the barrel calorimeter to hadrons with energies in the range 20-350 GeV and beam impact points and angles corresponding to pseudo-rapidity values in the range 0.2-0.65 are reported. The results are compared to the predictions of a simulation program using the Geant 4 toolkit.
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ATLAS Collaboration(Adragna, P. et al), Castelo, J., Castillo Gimenez, V., Cuenca, C., Ferrer, A., Fullana, E., et al. (2010). Measurement of pion and proton response and longitudinal shower profiles up to 20 nuclear interaction lengths with the ATLAS Tile calorimeter. Nucl. Instrum. Methods Phys. Res. A, 615(2), 158–181.
Abstract: The response of pions and protons in the energy range of 20-180 GeV, produced at CERN's SPS H8 test-beam line in the ATLAS iron-scintillator Tile hadron calorimeter, has been measured. The test-beam configuration allowed the measurement of the longitudinal shower development for pions and protons up to 20 nuclear interaction lengths. It was found that pions penetrate deeper in the calorimeter than protons. However, protons induce showers that are wider laterally to the direction of the impinging particle. Including the measured total energy response, the pion-to-proton energy ratio and the resolution, all observations are consistent with a higher electromagnetic energy fraction in pion-induced showers. The data are compared with GEANT4 simulations using several hadronic physics lists. The measured longitudinal shower profiles are described by an analytical shower parametrization within an accuracy of 5-10%. The amount of energy leaking out behind the calorimeter is determined and parametrized as a function of the beam energy and the calorimeter depth. This allows for a leakage correction of test-beam results in the standard projective geometry.
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ATLAS Tile Calorimeter Community(Abdallah, J. et al), Calderon, D., Castillo Gimenez, V., Costelo, J., Ferrer, A., Fullana, E., et al. (2013). Mechanical construction and installation of the ATLAS tile calorimeter. J. Instrum., 8, T11001–26pp.
Abstract: This paper summarises the mechanical construction and installation of the Tile Calorimeter for the ATLAS experiment at the Large Hadron Collider in CERN, Switzerland. The Tile Calorimeter is a sampling calorimeter using scintillator as the sensitive detector and steel as the absorber and covers the central region of the ATLAS experiment up to pseudorapidities +/- 1.7. The mechanical construction of the Tile Calorimeter occurred over a period of about 10 years beginning in 1995 with the completion of the Technical Design Report and ending in 2006 with the installation of the final module in the ATLAS cavern. During this period approximately 2600 metric tons of steel were transformed into a laminated structure to form the absorber of the sampling calorimeter. Following instrumentation and testing, which is described elsewhere, the modules were installed in the ATLAS cavern with a remarkable accuracy for a structure of this size and weight.
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