Bochum 2009 – wissenschaftliches Programm

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HK: Fachverband Hadronen und Kerne

HK 85: Accelerators and Instrumentation II

HK 85.7: Vortrag

Freitag, 20. März 2009, 12:30–12:45, H-ZO 90

Studies on SiPM radiation hardness and low light level detection — •Salvador Sanchez, Patrick Achenbach, and Josef Pochodzalla — Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz

A tracking detector based on two meters long scintillating fibers read out by silicon photomultipliers (SiPM) is being developed for the Kaos spectrometer at the Mainz Microtron MAMI. Low light level detection is challenging for these devices due to their high dark count rate. A relatively large cross-section of 4 mm² has been chosen as the optimum value for a minimal particle trajectories disturbance and a maximum detection efficiency. 100% detection efficiencies has been measured with an experimental prototype read out by a SSPM-0606BG4MM-PCB Photonique device at accidental coincidence rates of only a few Hertz. Because of the detectors close proximity to the intense electron beam a study of noise and radiation damage has been performed. SiPM have been irradiated with 14 MeV electron and exposed to mixed radiation in the experimental area. It is shown that the first noticeable damage consists of an increase in the rate of dark pulses and the loss of uniformity in the pixel gains. Realistic amounts of shielding have been tested and found to have only a relatively poor performance. Annealing has been proved to be only partially effective for SiPM recovery.