Non-ionising energy loss of radiation produces point defects and defect clusters in silicon, which result in a signifcant degradation of sensor performance. In this contribution results from TSC (Thermally Stimulated Current) defect spectroscopy for silicon pad diodes irradiated by electrons to fluences of a few $10^{14}$ cm$^{-2}$ and energies between 3.5 and 27 MeV for isochronal annealing between 80 and 280°C, are presented. A method based on SRH (Shockley-Read-Hall) statistics is introduced, which assumes that the ionisation energy of the defects in a cluster depends on the fraction of occupied traps. The dfference of ionisation energy of an isolated point defect and a fully occupied cluster, $ΔE_a$, is extracted from the TSC data.
For the VOi (vacancy-oxygen interstitial) defect $ΔE_a = 0$ is found, which cofirms that it is a point defect, and validates the method for point defects. For clusters made of deep acceptors the $ΔE_a$ values for different defects are determined after annealing at 80°C as a function of electron energy, and for the irradiation with 15 MeV electrons as a function of annealing temperature. For the irradiation with 3.5 MeV electrons the value $ΔE_a = 0$ is found, whereas for the electron energies of 6 to 27 MeV $ΔE_a > 0$. This agrees with the expected threshold of about 5 MeV for cluster formation by electrons. The $ΔE_a$ values determined as a function of annealing temperature show that the annealing rate is different for different defects. A naive diffusion model is used to estimate the temperature dependencies of the diffusion of the defects in the clusters.
硅光电倍增管（SiPM）中辐射损伤的主要影响是暗电流的急剧增加。如果没有适当冷却，耗散的功率会加热SiPM，其性能参数取决于温度。加热研究用KETEK SiPM进行，该SiPM胶合在Al $_2$ O $_3$衬底上，该衬底直接连接到探针台的温度控制卡盘，或者通过具有公知热阻的材料层连接。SiPM由在DC模式下操作的LED照明。测量SiPM电流，并将其用于确定稳态温度，该温度是SiPM倍增区域中耗散的功率和热阻的函数，以及加热和冷却的时间依赖性。该信息可用于校正辐射损伤SiPM的自热效应的参数。该方法还可以用于与散热器具有未知热接触的封装SiPM。本文的结果是初步的。
Silicon pinhole strip defects and their impact on ATLAS Inner Tracker HV current measurement
Santa Cruz Institute for Particle Physics, University of California at Santa Cruz（圣克鲁斯粒子物理研究所，加州大学圣克鲁兹分校）；Brandeis University（布兰迪斯大学）；University of British Columbia（不列颠哥伦比亚大学）；Brookhaven National Laboratory（布鲁海文国家实验室）；Rutherford Appleton Laboratory（卢瑟福·阿普尔顿实验室）；Simon Fraser University（西蒙菲莎大学）
