Heidelberg 2007 – scientific programme

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T: Fachverband Teilchenphysik

T 403: Halbleiterdetektoren III

T 403.2: Talk

Thursday, March 8, 2007, 17:00–17:15, KIP Gr. HS

Optische Einzelphotonenmessung mit DEPFET RNDR-Detektoren — •Stefan Wölfel^1,3, Sven Herrman^1,3, Peter Lechner^4,3, Matteo Porro^1,3, Rainer Richter^2,3, Lothar Strüder^1,3, and Johannes Treis^1,3 — ¹MPI für extraterrestrische Physik, Garching — ²MPI für Physik, München — ³MPI Halbleiterlabor, München — ⁴PNSensor GmbH, München

In this work we demonstrate theoretically and experimentally the capability to reduce the readout noise of an optical and X-ray photon detector based on the semiconductor DEPFET device below a level of only 0.3e⁻ ENC (equivalent noise charge). With such ultra low readout noise values it is possible to detect single photoelectrons produced after an optical photon interaction with silicon in terms of a real linear amplifier.

The readout method used is called "Repetitive Non Destructive Readout" (RNDR). By transferring the collected charge from one readout node (DEPFET 1) to the other (DEPFET 2) and vice versa the same charge can be measured non-destructively and arbitrarily often. Taking the average value of a large number n of these measurements, the noise is reduced by 1/√n. The main advantage of such a detector is to greatly reduce the influence of the 1/f noise to the readout noise. Single optical photon detection with high quantum efficiency and, even more fascinating, the possibility to distinguish between different numbers of photoelectrons e.g. 100 from 101 is presented in measurements.