Detailed investigation of Acceptor Removal in LGAD

A Low Gain Avalanche Diode (LGAD) sensor is developed for high-precision timing measurements. For applications of LGAD detectors in high-energy and high-luminosity hadron collider experiments, the detector must exhibit sufficient radiation tolerance against both Total Ionizing Dose (TID) and Non-Ionizing Energy Loss (NIEL) effects. In previous studies, the oxygen concentration in the sensor has been suggested to play a significant role in radiation-induced degradation, as the formation of $\mathrm{B_iO_i}$ complexes was considered a major cause of acceptor removal in the gain layer. In this study, we developed radiation-hard LGAD prototypes with reduced oxygen concentration using process improvements and the Partially Activated Boron method. Radiation tolerance was evaluated through depletion voltage and timing resolution measurements after irradiation with 45 MeV protons. The results show that the radiation tolerance of LGAD does not depend significantly on the oxygen concentration, suggesting that $\mathrm{B_iO_i}$ defects are not the dominant cause of acceptor removal in the gain layer.}