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This report by E. Monnier on behalf of the Atlas Liquid Argon Calorimeter group provides insights into the construction, integration status, and benchmark channels, ensuring energy resolution, angular resolution, linearity, particle identification, dynamic range, and more.
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Atlas liquid argon calorimeter statusE. Monnieron behalf of the Atlas liquid argon calorimeter group • Introduction • Construction and integration status • Performances • Conclusion E. Monnier - CPPM - ICHEP04 - Beijing
Design performances Benchmark channels: H→, H→4e, W’, Z’… + running conditions Design requirements: • energy resolution and uniformity σ/E = 10%/√E ⊕ 0.7% for e, σ/E = 50(100)%/√E ⊕ 3(10)% for jet |η|<3 (3<|η|<5) • Angular resolution: 50 mrad/√E for e, • Linearity of 0.1% for e, and <2% for hadronic • Particle id and separation: e, jets, , π0 • Dynamic range 20 MeV to a few TeV • Time measurements, Hermiticity, Radiation…. E. Monnier - CPPM - ICHEP04 - Beijing
EM Endcap Ps |η|<1.8 EM Barrel+Ps Hadronic Endcap Forward The Atlas larg calorimeters • Em barrel |η|<1.475 (Pb/Lar) • Em endcap 1.375<|η|<3.2 (Pb/Lar) • Hadronic endcap 1.5<|η|<3.2 (Cu/Lar) • Forward 3.2<|η|<4.9 (Cu, W/Lar) > 200000 channels E. Monnier - CPPM - ICHEP04 - Beijing
e EM Barrel 32 Modules cold tested and integrated MC Barrel Closed cooled down • <0.014% dead channels ! • 0.1% HV ½ gap isolated • Barrel at LArg temperature • Under extensive test • In the pit early October E. Monnier - CPPM - ICHEP04 - Beijing
Endcap: EM 1/4 8 Modules cold tested and integrated Per wheel ! E. Monnier - CPPM - ICHEP04 - Beijing
Space to insert Fcal Hec2, Hec1, Emec Endcap: HEC 2/4 32 Modules cold tested and integrated Per wheel (2x2) E. Monnier - CPPM - ICHEP04 - Beijing
Endcap: FCAL 3/4 3 Modules cold tested and integrated per wheel Cu (em) W (had) E. Monnier - CPPM - ICHEP04 - Beijing
Endcap 4/4 • EC C, Em+Had+Fcal integrated • Closed and ready for cold test • EC A, Em integrated, Had under integration, Fcal ready for integration • Em: <0.005% dead channels and 0.1% HV ½ gap isolated • Hec: 0.03 % dead channels and 0.14% HV gap isolated • Fcal: 0.03, 0.17 and 0.55 % of HV Rod isolated Calorimeter system moving toward commissioning phase !! E. Monnier - CPPM - ICHEP04 - Beijing
Beam test Performances • 4 barrel and 3 endcap EM production modules tested • 24 HEC prod modules tested (3 frt+3 rear/test) • Fcal-C tested • HEC/EMEC combined test EM Barrel EM End-cap EMEC/HEC E. Monnier - CPPM - ICHEP04 - Beijing
Normalized to 100 GeV η=0.7 9.4% /E0.1% Energy resolution Linearity (Erec/Ebeam) Beam energy (GeV) Beam energy (GeV) EM linearity and energy resolution • Linearity within ±0.25 (0.1)% for E>10 (40) GeV • Energy resolution within spec and MC agreement E. Monnier - CPPM - ICHEP04 - Beijing
EM Uniformity Barrel EndCap Energy (GeV) η (middle) Energy (GeV) Global constant term within spec (0.7%) E. Monnier - CPPM - ICHEP04 - Beijing
Position and angular resolution 245 GeV e ~550 mm at =0 resolution ( units x 1000) ~250 mm at =0 sZ~20mm Barrel 55 mrad/√E sθ(mrad) x √E within spec Endcap ~1.7 sZ~5mm Barrel 20 100 150 Energy (GeV) E. Monnier - CPPM - ICHEP04 - Beijing
Barrel Time resolution (ps) Cell energy (GeV) Time measurement • Fast signal in Argon accurate time measurement • Zvertex measurement, long lived particle id,… • Front end electronic very low constant term < 20ps • 70ps constant term within spec (100ps) E. Monnier - CPPM - ICHEP04 - Beijing
Endcap Muon measurements • Muon signal large enough in middle layer but also seen in strips: • S/N = 7 Endcap S2 • S/N = 7-10 in Barrel S2 • Seen also in HEC Barrel Powerful tool for commissioning: intercalibration (1ns), position (0.5mm EM, mms HEC), uniformity (<3‰ EM, 1% HEC) … E. Monnier - CPPM - ICHEP04 - Beijing
(84.1 0.3)% /E Emec/Hec combined test • Emec + Hec (3frt+2rear), non pointing geometry • Study 1.6<||<1.8 calibration constants for atlas • e/h compensation: weighting of em cluster energy • MC validation: room for improvement E. Monnier - CPPM - ICHEP04 - Beijing
a=(3.760.06)% b=(24.50.84)GeV % c=(145.51.6) GeV% σ/E (%) E (GeV) Fcal calibration run Electron energy resolution • FCAL energy calibration • Edge scan at high || + HV test E. Monnier - CPPM - ICHEP04 - Beijing
MDT-RPC HEC front Warm TC Tilecal HEC rear EMEC TRT LAr FCAL 2 FCAL 1 Cold TC 2004 beam tests (the last before LHC) Combined tests with “final” atlas setup and readout • Barrel: Tracker, EM, hadronic calo, Muons system • End-cap: EM, HEC, FCAL • Tuning ATLAS hardware, online and offline software, calibration… E. Monnier - CPPM - ICHEP04 - Beijing
1 March 2004 Next April 2004 2005: EC cryostats… October 2004 2005: Install electronics E. Monnier - CPPM - ICHEP04 - Beijing
Conclusions • Larg calorimeter system in its final integration stage before installation in the pit: October for barrel • Beam tests have exhibited required performances • Combined 2004 beam test with final ATLAS readout system ongoing successfully • Readout electronic under production • Commissioning phase will start next year But still a lot of work and understanding of the system to be ready for first data in 2007 E. Monnier - CPPM - ICHEP04 - Beijing