Strategies for shortening the output pulse of silicon photomultipliers

Abstract

In this work, three strategies for shortening the output pulse of a silicon photomultiplier (SiPM) are reported. The first strategy is passive filtering, where band-pass filtering removes the lowest frequency components in the signal, getting a noticeable reduction in pulse width (a compression ratio of 10: 1 was obtained). In the second place, a reflectometric scheme is proposed where the amplified signal coming from the SiPM is injected into a signal splitter with one of its stubs connected to a short-circuited stub. In the last strategy, the reflectometric part is replaced by an analog subtractor circuit. In this approach, a signal splitter with stubs of different lengths is used. All solutions provide good compression ratios, up to 10: 1. Best pulses obtained are single narrow peaks, with width below 10 ns, preserving the photonic modulation and with good pseudo-Gaussian shape, single polarity and low ringing. The potential of pulse shortening for improving the capability of the detector to resolve single photons is demonstrated by mean of single photon counting patterns. The detection error probability is reduced in one order of magnitude when shortening is used for conditioning the output photosignal.