PROPERTIES OF BORON IMPLANTED LGAD TIMING DETECTORS

For the high luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN starting in the middle of 2026 after the 3r d long shutdown. The HL-LHC will be operating at √s = 14 TeV and reaching a peak instantaneous luminosity of 5 x 1034 cm−2 s−1 (7.5 x 1034 cm−2 s−1) which corresponds to 140 (200) inelastic p-p collisions per beam crossing. This is one of the difficult challenges ATLAS is facing because, of the huge amount of collisions and luminosity. As a result, ATLAS is proposing a High Granularity Timing Detector (HGTD) to be installed in front of the end-cap calorimeters with Low Gain Avalanche Detectors (LGAD) chosen as preferred timing detectors. A beam test campaign has been conducted to study the properties of these new detectors under severe conditions in June 2018 with a high-energy pion beam of 120 GeV at the H6A line in the CERN SPS. This study aims to pick the best detector that fulfills the requirements of HGTD. This paper is comparing two boron single pad sensors CNM10478 W5S1038 (44.82±0.47) ps for 220V and CNM9088 LGA35 (33.82±0.12) ps for 190V. As a result the CNM9088 LGA35 sensor showed better timing resolution. The time reconstruction method carried out is the Constant Fraction Discriminator (CFD).