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HK: Fachverband Physik der Hadronen und Kerne

HK 22: Instrumentierung IV

HK 22.6: Vortrag

Dienstag, 16. März 2010, 15:30–15:45, HG IX

Characterization of LN2 cooled APDs for Single Photon Counting Applications — Denis Anielski¹, Wladimir Buglak¹, •Raphael Jöhren¹, Volker Hannen¹, Rubén Lopéz Coto¹, Wilfried Nörtershäuser^2,3, Rodolfo Sánchez³, and Christian Weinheimer¹ — ¹Institut für Kernphysik, Universität Münster — ²Institut für Kernchemie, Universität Mainz — ³GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt

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 1064 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 SNR 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 tailored to operation at low temperatures inside the vacuum has been developed. We will present the latest 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.