Speaker
Taka Kondo
(High Energy Accelerator Research Organization (JP))
Description
The Silicon micro-strip tracker (SCT) of the ATLAS experiment at LHC has
been running for physics at 7 and 8 TeV over 3 years. The integrated
delivered luminosity to ATLAS is 29.5 fb-1 and the fluence at the inner
most SCT modules corresponds to about 5e12 1MeV-equivalent neutrons/cm**
2, the level below the type inversion. More than 99% of 4088 modules
areactive with very high efficiency. During the beam time, all modules
are cooled uniformly and stably within 2 degree C of their specified
temperatures. The HV current drawn has been steadily increasing from 100
nA to 100 uA per module. The current increase observed in the barrel
region is in very good agreement with predictions of the silicon
bulk leakage current models with self-annealing effects without any
parameter adjustment. Calibration runs have been performed frequently to
monitor the noise and gain, both of which have been fairly stable with
some exceptions. Modules with CiS sensors have been showing mysterious
beam-associated behavior in the HV current and some of these modules
were kept below nominal bias voltage of 150V.
