Speaker
Description
The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to $10^{34}$ cm$^{-2}$ s${^-1}$. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudorapidity region $|\eta|<3.2$, and for hadronic calorimetry in the region from $|\eta|=1.5$ to $|\eta|=4.9$.
The calibration and performance of the LAr calorimetry system was
established during beam tests, cosmic ray muon measurements and in
particular the first three years of pp collision data-taking. During
this period, referred to as Run-1, approximately 27~fb$^{-1}$ of data
have been collected at the center-of-mass energies of 7 and
8~TeV. Following a period of detector consolidation during a long shutdown,
Run-2 started in 2015 with approximately 3.9~fb$^{-1}$ of data
at a center-of-mass energy of 13~TeV recorded in this year. Results
on the LAr calorimeter operation, monitoring and data quality, as well as
their performance will be presented, including the
calibration and stability of the electromagnetic scale, response
uniformity and time resolution. These results demonstrate that the
LAr calorimeters perform excellently within their design
requirements. The calorimetry system thus played a crucial role in the
Run-1 physics programme, and, in particular, in the discovery of a Higgs boson.
