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HK: Fachverband Physik der Hadronen und Kerne
HK 32: Instrumentation 12
HK 32.7: Vortrag
Dienstag, 24. März 2015, 18:30–18:45, M/HS4
SiPM properties at cryogenic temperatures — •Maik Biroth1, Patrick Achenbach1, Evangeline Downie2, and Andreas Thomas1 for the A2 collaboration — 1Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz, Germany — 2George Washington University, DC, USA
At the electron accelerator Mainzer Mikrotron (MAMI) an active target build of polarizable scintillators will be operated at approximately 25 mK. To read out the scintillation light, the photodetectors have to withstand cryogenic temperatures of 4 K and high count rates. Therefore the properties of different types of silicon photomultipliers (SiPMs) were studied at cryogenic temperatures. In liquid nitrogen at 77 K, problems with quenching in Hamamatsu SiPMs and with the protective epoxy layer covering Zecotek SiPMs were observed. Tests with one Zecotek SiPM were successful after removal of the epoxy layer in liquid helium at 4 K and no after-pulses could be observed. Fundamental parameters like break-down voltage, single-pixel gain, crosstalk probabilty and the dark-count rate were measured and compared to room temperature. The photon detection efficiency was estimated by SiPMs response to short LED pulses. All these parameters were extracted by curve-fitting of SiPM charge spectra with a new analytical function.