Liquid Argon Calorimeter

1. middle cell depth 45.8 data 28.3 19.7 17.6 16.1 16.8 MeV |E|<300 MeV U EMB EMEC t Calibration pulse Physics pulse Maximum proportionnal to energy deposit :2.8 A/GeV I Calibration t Trigger L1 L1 decision Drift Time ~ 400 ns ADC ROD E =  ai ADCi E.τ =  bi ADCi SCA Cryostat Shaper CR-RC2 reconstructed energy and time using anOptimal Filtering Method HEC FCal U HV t Absorber Detection Cell Physics pulse after shaping   Cosmic Trigger Module P4 TOP A ~3100 hits 5 1 2 6 Module P5 Z ~3200 hits 7 3 3 4 8  BOTTOM B η=0 η=0.8 η cell center (Xo,Zo) Y=0 TileCal Muon Fitter The ATLAS Liquid Argon Calorimeter Commissioning Hong Ma, Fabien Tarrade Brookhaven National Laboratory, New York The ATLAS liquid argon (LArg) calorimeter system consists of an electromagnetic (EM) barrel calorimeter and two end caps with EM, hadronic and forward calorimeters. The ATLAS EM barrel (EMB) and the two end cap (EMEC, HEC and FCal) calorimeters were installed in the ATLAS cavern and the front-end electronics are being connected and tested. Liquid Argon Calorimeter Signal Reconstruction • Electromagnetic Barrel (EMB) accordion geometry Pb-LArg 101,760 readout channels • Electromagnetic Endcap (EMEC) accordion geometry Pb-LArg 62,208 readout channels • Presampler active layer LArg 7,808 (barrel), 1536 (endcaps) channels • Hadronic Endcap (HEC) plate geometryCu-LArg 5,632 readout channels • Forward Calorimeter (FCal) matrixCu/Tungsten-LArg 3,524 readout channels 182,468 cells for Liquid Argon Calorimeter dead readout channels much below that 1% • Electromagnetic Barrel Readout chain energy E : - pedestal P - Optimal Filtering Coefficient ai - ADC→MeV F construction and installation in the pit: finished all detectors filled with LArg : 89 K;HV :partial electronics’ installation/commissioning : on going all sub-detectors with similar LArg signal pulse shapes pedestal, noise auto-correlation function, and signal shape  from commissioning Commissioning Goals and Results Cosmic Ray Running dead cell • Commissioning Goals • basicdetector functionality • - exercise Front-End electronics • - look for dead/bad channels • - cabling, channel mapping • -measure noise • - readout/trigger chain • - full LVL1/TDAQ/online/offline chain • - interfaces between : DAQ, DCS, DB • calibrationrun • - check pulse shapes • - initial calibration constants • - measure cross-talk • cosmics commissioning run • -check pulse shapes with cosmic muons • - signal reconstruction • - signal/noise separation • - check/adjust detector timing at 1 ns level • - check cell response uniformity at 1% level • - calorimeter position with respect to other detectors (<1 mm) • Trigger and Data Acquisition 8 dedicated trigger boards using TileCal: - 4 barrel - 4extended barrel data taken ~weekly + without 2nd filter + with 2nd filter 17 MHz noise • Muon ID and LArg clustering pedestal RMS (ADC) -barrel : use middle layer: muon S/N ~ 7 - endcap: muon S/N ~2-5 (EMEC & HEC but not FCal) check with TileCal algorithm to find a muon track channel number 50 pulsed middle cell neighbor strips long distance strips • LArg Timing amplitude (ADC) 50 use TileCal to get timing of the muon at y=0 plane correct for TOF to EM (middle layer) -check cable lengths, descriptions, offsets - tune timing reconstruct LArg energy cross-talk, EMB t (ns) simulation of 10 ms of cosmics muon timing studies energy reconstruction energy reconstruction EMEC2 HEC0 (with all conditions data) (with all conditions data) EM time from OFC (ns) need 70 000 projective muons  3 months data-taking TileCal time corrected for TOF (ns) LArg energy LArg energy Cosmic Muon Results Conclusions & Outlook • Conclusion event display • Cosmics Commissioning Results interferences/interplay: -between sub-detectors -and with trigger calibration data provide : -a good understanding of the LArg waves -first calibration coefficients cosmics data provide a first understanding : - timing - uniformity - energy reconstruction of the ATLAS LArg calorimeters from 5 samples to 29 samples : noise reduced by a factor of 1.7 uniformity : error bar per point is ~2 % on average (top 3-4%, bottom 1-2%) to check 1% non uniformity at cell level : average 16 times more statistics normalized ~9200 muons noise (MeV) f(x)=p0 + p2*exp(p1*x) uniformity TOP noise reduction BOTTOM • Outlook continue commissioning with cosmic muonswith commissioning of the LCH machineuse : -beam halo -beam-gas collisions normalized to 1  be ready for the first collision in July 2008 number of sample