Study of first thin LGAD prototypes for the ALICE 3 timing layers

The work here presented concerns the characterization and the performance study of very thin Low-Gain Avalanche Detector (LGAD) prototypes; the goal is to evaluate if such a sensor is suitable for the Time-Of-Flight (TOF) system of the ALICE 3 experiment, a next generation heavy-ion experiment (LHC Run 5). A total of 18 sensors with a thickness of 25 μm and 35 μm were characterized; both single channel and matrices, with different inter-pad design and doping profile were compared to two 50 μm-prototypes. Preliminary tests with a laser setup allowed to evaluate the light-sensitive areas in terms of efficiency, uniformity of the response and edge effects. Finally, timing performances were analyzed. Promising results were found for the 25 μm-thick sensors, which showed a time resolution better than 16 ps for a gain 20 and reaching nearly 13 ps for a gain 30.