Bochum 2009 – scientific programme
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HK: Fachverband Hadronen und Kerne
HK 67: Poster Session
HK 67.77: Poster
Thursday, March 19, 2009, 14:00–16:00, Audi-Max
Characterization of LN2 Cooled APDs for Single Photon Counting Applications — Denis Anielski1, Wladimir Buglak1, Daniel Hampf2, Volker Hannen1, •Raphael Jöhren1, and Christian Weinheimer1 — 1Institut für Kernphysik, Universität Münster — 2Institut für Experimentalphysik, Universität Hamburg
Avalanche Photo Diodes (APDs) operated near LN2 temperature are one of the technologies under investigation for the detection of low levels of fluorescence light produced in the laser spectroscopy experiment SPECTRAP at GSI. Measurements of hyperfine transitions in highly charged ions require single photon detection capabilities from the UV to the near infrared. With high quantum efficiencies in the visible and NIR region (up to 1020 nm), APDs are a possible candidate for measurements of the hyperfine transitions e.g. in 207Pb81+. Problems arise due to large dark count rates of the APDs when operated at room temperature or with modest cooling only. To characterize dark current, gain and signal to noise ratio of the detectors as a function of temperature and bias voltage, a LN2 cooled cryogenic test bed has been set up at the nuclear physics institute in Münster. To minimize the noise contribution from external sources a low noise preamplifier board tailored to operation at low temperatures inside the vacuum has been developed based on the AMPTEK A250 chip. We will present results regarding the performance of the preamp design and the temperature behavior and photon detection efficiency of the tested APDs.
This work is supported by an R&D contract with GSI.