Speaker
Mrs
Ludovica Aperio Bella
(LAPP)
Description
The ATLAS experiment is designed to study the proton-proton collisions
produced at the Large Hadron Collider(LHC) at CERN. Liquid argon
sampling calorimeters are used for all electromagnetic calorimetry
covering the pseudo-rapidity region up to 3.2, as well as for hadronic
calorimetry in the range 1.4-4.9. The electromagnetic calorimeters use
lead as passive material and are characterized by an accordion
geometry that allows a fast and uniform azimuthal response without any
gap. Copper and tungsten were chosen as passive material for the
hadronic calorimetry; whereas a classic plate geometry was adopted at
large polar angles, an innovative one based on cylindrical electrodes
with thin argon gaps was designed for the coverage at low angles,
where the particles flow is higher. All detectors are housed in three
cryostats kept at 87 K. After installation in 2004-2006, the
calorimeters were extensively commissioned over the three years period
prior to first collisions in 2009, using cosmic rays and single LHC
beams. Since then, around 5 fb$^{-1}$ of data have been collected at a
center of mass energy of 7 TeV. During all these stages, the
calorimeter and its electronics have been operating almost optimally,
with performances very close to the specification ones. The talk will
cover all aspects of these first years of operation, including the
calibration efforts, the data quality assessment procedure, and the
final performance.
for the collaboration
ATLAS Liquid Argon Calorimeter Group
