Speaker
Description
Low Gain Avalanche Detectors (LGADs) have proven their suitability for precise timing in high-energy physics experiments and are therefore foreseen for the HL-LHC upgrades of the ATLAS and CMS detectors at CERN. Their performance, however, is limited by radiation-induced gain layer degradation, mainly due to acceptor removal. This study investigates irradiation with 18MeV, 24MeV, 400MeV and 23GeV protons in order to explore deviations from the commonly assumed Non-Ionizing Energy Loss (NIEL) scaling hypothesis. The motivation for examining different proton energies is that lower energies are expected to produce predominantly point defects, while higher energies generate more clustered defects, leading to distinct degradation mechanisms that cannot be fully described by NIEL scaling.
Measurements were carried out on LGADs from HPK and IMB-CNM, covering devices with variations such as carbon co-implantation aimed at mitigating defect formation. From the initial electrical characterization (I-V and C-V), acceptor removal coefficients were extracted, which quantify the degradation of the gain layer as a function of fluence. The results show enhanced degradation at low proton energies compared to higher energies. However, the dependence does not follow a simple monotonic relation between energy and damage, but instead points to a more complex energy dependence. Complementary laser and radioactive source measurements were performed to further investigate these trends and to probe the gain and timing performance of the irradiated samples. The results of this study provide first insights into the complex energy dependence of gain layer degradation under proton irradiation and can deliver valuable input for future LGAD design and radiation damage modeling.
| Type of presentation (in-person/online) | in-person presentation |
|---|---|
| Type of presentation (I. scientific results or II. project proposal) | I. Presentation on scientific results |
