Speaker
Description
Svetlana Kushpil for the ALICE Collaboration
The Inner Tracking System (ITS2) of the ALICE experiment at the CERN
Large Hadron Collider is based on a Monolithic Active Pixel Sensor technology.
Installed during the Long Shutdown 2 (LS2), it has been operating in LHC
Run 3 and successfully collected data from pp, Pb–Pb, O–O, Ne–Ne collisions.
The ITS2 consists of seven concentric layers of ALPIDE monolithic active pixel
sensors produced in the TowerJazz 180 nm CMOS process, covering a total sen-
sitive area of about 10 m2. The sensor features a pixel pitch of 27 μm × 29
μm and a position resolution of about 5 μm. The very low material budget,
amounting to 0.36% X0/layer for the three innermost layers and 1.10% X0/layer
for the outer layers, in combination with the small radial distance of only 23
mm from the beam, leads to an excellent impact parameter resolution at low
transverse momentum, which is crucial to reconstruct low transverse momen-
tum heavy-flavor particles in the heavy-ion collision environment. To ensure
stable operations and maintain high data quality, the synchronous monitoring
of the detector operating parameters and the asynchronous reconstruction of the
collected data are performed through the data Quality Control system (QC).
Regular calibration procedures are carried out to determine the charge thresh-
olds and identify noisy channels of the detector. This contribution gives an
overview of the operational procedures required to maintain an optimal data
quality, along with results obtained from calibrations and the QC system. The
monitoring for fake-hit rate, front-end electronics status, data integrity, clus-
ter and track distributions, threshold and noise calibrations will be presented,
together with the detector performance achieved in different collision systems
during LHC Run 3.