Analysis of the Drift Velocity of the Silicon Drift Detector for ALICE Experiment

0486521 - ÚJF 2018 US eng C - Conference Paper (international conference)
Kushpil, Svetlana
Analysis of the Drift Velocity of the Silicon Drift Detector for ALICE Experiment.
IEEE Nuclear Science Symposium Conference Record. Vol. 2012. New York: IEEE, 2012, s. 1349-1352. ISBN 978-1-4673-2030-6. ISSN 1082-3654.
[IEEE Nuclear Science Symposium / Medical Imaging Conference Record (NSS/MIC) / 19th Room-Temperature Semiconductor X-ray and Gamma-ray Detector Workshop. Anaheim (US), 29.10.2012-03.11.2012]
Institutional support: RVO:61389005
Keywords : Inner Tracking System * ALICE experiment * calibration strategy
Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

Silicon Drift Detectors (SDD) equip the two intermediate layers of the Inner Tracking System (ITS) of the ALICE experiment. The SDD is required to provide a spatial precision of about 35 mu m along the drift direction and 25 mu m along the anode axis. In these detectors, the drift velocity depends on temperature (upsilon proportional to T-2.4), giving a 0.8%/K variation at room temperature. To achieve the required resolution on the drift coordinate, it is necessary to assure a temperature stability within 0.1 K.

The drift velocity is determined by measuring the drift time of electrons injected in the sensor volume in fixed positions by means of dedicated MOS devices (injectors). We report the current calibration strategy, the operational experience and the injector performance during the 2010-12 data taking period. Studies of drift velocity stability as a function of time were carried out in different periods and for two different configurations of the SDD cooling system. We also show the results of a study of the time needed to stabilize the temperature after ramping up the detector high voltage. This measurement is important for the detector operation because the high voltage is ramped down and up at each LHC fill during the beam injection.
Permanent Link: http://hdl.handle.net/11104/0281307