10th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Xi'an, China

Development of n-in-p pixel modules for the ATLAS upgrade at HL-LHC

27 Sept 2015, 09:20

20m

International Hall (International Conference Center (Nanyang Hotel))

ORAL Pixels (including CCD's) - Charged particle tracking Pixels (including CCD's)-2

Speaker

Anna Macchiolo (Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D)

Description

Thin planar pixel modules are promising candidates to instrument the inner layers of the new ATLAS pixel detector for HL-LHC, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. 100-200 um thick sensors, interconnected to FE-I4 read-out chips, have been characterized with radioactive source scans and beam tests at the CERN-SPS and DESY. The results of these measurements will be discussed for devices before and after irradiation up to a fluence of $1.5x10^{16}$ n$_{eq}$ cm$^{-2}$. The charge collection and tracking efficiency will be compared for the different sensor thicknesses. The outlook for future planar pixel sensor productions will be discussed, with a focus on sensor design at the pixel pitches (50x50 and 25x100 µm²) foreseen for the RD53 Collaboration read-out chip in 65 nm CMOS technology. An optimization of the biasing structures in the pixel cells is required to avoid the hit efficiency loss presently observed in the punch-through region after irradiation. For this purpose the performance of different layouts have been compared in FE-I4 compatible sensors at various fluence levels by using beam test data at DESY and CERN-SPS. Highly segmented sensors will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. In order to reproduce the performance of 50x50 µm² pixels at high eta, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angle (80º) with respect to the short pixel direction. Results on cluster shapes, charge collection and hit efficiency will be shown.

Presentation materials

Macchiolo_V1.pdf