پیشرفت های اخیر از پروژه "تحقیق و توسعه" حسگر پیکسلی دو وجهی ATLAS

The foreseen luminosity upgrade for the LHC (a factor of 5-10 more in peak luminosity by 2021) poses serious constraints on the technology for the ATLAS tracker in this High Luminosity era (HL-LHC). In fact, such a luminosity increase leads to increased occupancy and radiation damage of the tracking detectors. To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Planar Pixel Sensor R&D Project was established comprising 17 institutes and more than 80 scientists. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edge designs to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. In the following I will present results from the group, concerning mainly irradiated-devices performance, together with studies for new sensors, including detailed simulations.

Consisting of three barrel layers (at radii between 50.5mm and 122.5mm), and six discs, the pixel detector counts a total of 1744 pixel modules, which are mounted allowing for a three-hit track-reconstruction of charged secondary-particles. Each module contains a 250 μm thick n-in-n pixel sensor of 62.6 × 18.6mm2 with pixel cells of 50×400 μm2. Connected to each sensor are 16 7.4×11.0mm2 ATLAS FE-I3 [6] readout chips with a total of 46080 channels. Both the sensors as well as the electronics of the present ATLAS pixel modules were specified to work up to a fluence of 1015neq/cm2 and an ionising dose of 50 MRad.