Speaker
Description
Detectors used in high energy physics experiments will need to keep sufficient performance during a few years of data-taking, despite the accumulation of radiation damage, which, for example, in the planned upgrades of the LHCb and Belle II experiments, is estimated at about 10¹³ 1-MeV neutron equivalent/cm² by detector end-of-life. In this work, 6 NUV-HD-RH silicon photomultiplier (SiPM) samples developed by the Fondazione Bruno Kessler (FBK) with the purpose of improving the SiPM radiation hardness were characterized before and after irradiation. Each sample has 3 wire-bonded 1x1 mm² 15 µm pitch SiPMs with different structures. In total, 18 SiPMs, 6 SiPMs of the same structure, were characterized before irradiation. 5 of the samples were irradiated at the JSI TRIGA reactor with different fluencies: 10⁹ neq/cm², 10¹⁰ neq/cm², 10¹¹ neq/cm², 10¹² neq/cm² and 10¹³ neq/cm², while leaving one of the samples non-irradiated for crosscheck. In total, 15 SiPMs, 5 SiPMs of the same structure, were re-characterized after irradiation. The sample irradiated at 10⁹ neq/cm² was annealed at room temperature and its 3 SiPMs (one per structure) re-characterized after 1 month of annealing. For the SiPM characterization in all the cases, I-V curve measurements, threshold scan, and waveform analysis, including single photon time resolution, were carried out at room temperature and at different controlled temperature steps down to liquid nitrogen temperature.
