R. Jöhren, R. Berendes, W. Buglak, D. Hampf, V. Hannen, J. Mader, W. Nörtershäuser, R. Sánchez, C. Weinheimer
For the SPECTRAP experiment at GSI, Germany, detectors with Single-Photon counting capability in the visible and near-infrared regime are required. For the wavelength region up to 1100 nm we investigate the performance of 2x2 mm^2 avalanche photo diodes (APDs) of type S0223 manufactured by Radiation Monitoring Devices. To minimize thermal noise, the APDs are cooled to approximately -170 deg. C using liquid nitrogen. By operating the diodes close to the breakdown voltage it is possible to achieve gains in excess of 2x10^4. Extremly low noise preamplifiers are used to read out the devices. The measurements presented in this paper have been obtained at a gain of 22,000. At a discriminator threshold of 6 mV the resulting dark count rate is in the region of 200/s. With these settings the studied APDs are able to detect single photons at 628 nm wavelength with a photodetection efficiency of (67+-7)%. Measurements at 1020 nm wavelength have been performed using the attenuated output of a grating spectrograph with a light bulb as photon source. With this setup the photodetection efficiency at 1020 nm has been determined to be (13+-3)%, again at a threshold of 6 mV.
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http://arxiv.org/abs/1111.6948
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