The track timing detectors at HL-LHC will use Low Gain Avalanche Detectors, a technology that emerged several years ago and has attracted attention of many semiconductor producers. The intensive R&D over the past years resulted in a technology that is mature enough to cover the areas comparable to trackers. Although produced in standard planar technology, their application as timing detectors differ from hybrid strip/pixel detectors. The principles of operation, timing and charge collection performance of different sensor designs together with modelling will be presented. In particular, the design and performance of the sensors foreseen for the CMS Endcap Timing Layer (ETL) and the ATLAS High-Granularity Timing Detector (HGTD) pre and post irradiation will be covered. An emphasis will be put on understanding the gain layer design, radiation effects on LGADs and Single Event Burnout (SEB) events at high voltages. The requirements and prototype performance of the ASICs will be also discussed.
Dominik Dannheim (EP-DT)