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T: Fachverband Teilchenphysik
T 57: Calorimeters I
T 57.3: Vortrag
Mittwoch, 17. März 2021, 16:30–16:45, Tg
Investigation of neutron-induced radiation damage on SiPMs — •Laura Büttgen, Erika Garutti, and Jörn Schwandt — Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Deutschland
Silicon Photomultipliers are photosensors employed in many HEP detectors. Their radiation hardness is subject of intense investigation. For the upgrade of the CMS detector SiPMs should be exposed to fluences up to 5× 1013 cm−2 in the High Granularity Calorimeter (HGCAL) and up to 2× 1014 cm−2 in the barrel timing layer. In this study twenty SiPMs from Hamamatsu with the serial number S14160-9766 and S14160-9768 were characterized and the effects of neutron irradiation with different fluences were analyzed. For the analysis current-voltage measurements, capacitance-frequency-voltage measurements and charge-voltage measurements have been performed.
Due to irradiation an increase of six orders of magnitude of dark current was found after irradiation. Furthermore an evidence of the decrease of the photodetection efficiency after irradiation will be presented. The quantification of the reduction is still subject of investigation and may depend on the effect of self-heating of the SiPM. As self-heating effects one describes the increase of temperature induced in the SiPM pixels by high currents, for instance due to high frequency dark noise, or light detection. Variations in temperature lead to a shift in the breakdown voltage, which if not corrected causes a change of all SiPM performance parameters. This effect is also described and first measurements are attempted to quantify it.