Study of Low Gain Avalanche Diodes for the phase-II Upgrade of ATLAS High-Granularity Timing Detector

Abstract

The thesis reports the performance of the low gain avalanche sensors for High Granularity Timing detector (HGTD). HGTD, based on low gain avalanche detector technology, which has been proposed for the ATLAS Phase-II upgrade. Covering the pseudorapidity region between 2.4 and 4.0, with a timing resolution of 30 ps for minimum-ionizing particles, this device will signi - cantly improve the performance in the forward region. High-precision timing greatly improves the track-to-vertex association, leading to a performance similar to that in the central region for both jet and lepton reconstruction, as well as the tagging of heavy- avour jets. The sensors that we analyzed were made by Hamamatsu photonics (HPK) of di erent wafer sizes. We analyzed the sensors for the basics requirements of the HGTD like waveform amplitude, charge and time resolution. The data were collected during March- 2019 test-beam campaign at DESY. We found that those sensors which were highly irradiated with proton and neutrons shows poor performance compare to un-irradiated and low ounced sensors.