Study of total ionization does effects on IHEP-NDL LGAD sensors

A High-Granularity Timing Detector (HGTD) , based on low-gain avalanche detector (LGAD) technology, is proposed for the ATLAS Phase-II upgrade. In order to operate in harsh environment in high luminosity LHC, One of the most important parameters of the HGTD is radiation hardness of the sensors and electronics. This contribution focuses on total ionization does (TID) effects on LGAD sensors developed by NDL (Novel Device Laboratory) and IHEP. IHEP-NDL sensors are irradiated up to 3MGy using Multi-Rad 160 X-ray irradiator . In order to study the sensor surface damage due to TID effects, we measure the inter-pad isolation and surface leakage current of various 2x2 LGAD sensors with different doping profile, epitaxial resistance and guardring design. The surface damage due to TID effects are also measured performing laser test and beta source tests on IHEP-NDL sensors.