ATLAS LAr calorimeter performance in LHC Run-2

摘要

The Liquid-argon (LAr) sampling calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudo-rapidity region In vertical bar eta vertical bar 3.2, and for hadronic and forward calorimetry in the region 1.5 vertical bar eta vertical bar 4.9. In the first LHC run a total luminosity of 27 fb(-1) has been collected at centre-of-mass energies of 7-8 TeV. After detector consolidation during a long shutdown, Run-2 started in 2015 and 86.4 fb(-1) of data at a centre-of-mass energy of 13 TeV have been recorded. In order to realise the level-1 acceptance rate of 100 kHz in Run-2 data taking, the number of readout samples recorded and used for the energy and the time measurement has been modified from five to four while keeping the expected performance. The well calibrated and highly granular LAr calorimeter reached its design values both in energy measurement as well as in direction resolution. This contribution will give an overview of the detector operation, hardware improvements, changes in the monitoring and data quality procedures required to cope with increased pileup, as well as the achieved performance, including the calibration and stability of the electromagnetic scale, noise level, response uniformity and time resolution.