Speaker
Description
The High Granularity Timing Detector (HGTD) project of ATLAS will reduce the pile-up effect in HL-LHC by providing precise time measurement of tracks. The Low- Gain Avalanche Detector (LGAD) with time resolution better than 35(70) ps before(after) irradiation is the key technology which has been studied by many institutes. The Institute of High Energy Physics Chinese Academy of Science (IHEP) has been developing LGAD sensors IHEP-IME with the Institute of Microelectronics of the Chinese Academy of Sciences (IME). So far two versions of IHEP-IME LGAD sensors has been produced, IHEP-IMEv1 and IHEP-IMEv2. IHEP-IMEv1 sensors showed good potential in achieving the HGTD requirements with time resolution better than 60 ps and 4 fC charge collection around 700 V after irradiation. IHEP-IMEv2 sensors have modified doping profile compared with last version, especially focusing on the carbon implantation effect. Sensors with diverse producing process and carbon dose were fabricated and have showed improved performance. This talk will present the test results of IHEP-IMEv2 sensors irradiated with fluences of 0.8 ×1015 neq/cm2, 1.5 ×1015 neq/cm2 and 2.5×10 neq/cm2 and compare them with results before irradiation. After irradiation, sensors with different carbon dose showed different performance. The effect of carbon implantation will be shown. Low temperature beta test results showed that, after 2.5×10 neq/cm2 irradiation sensors collect 4 fC at less than 400 V with time resolution better than 50 ps, by far satisfying the requirements.
