Miniaturized read-out interface “Spectrig MAPD” dedicated for silicon photomultipliers

Abstract The new pocket size read-out interface device dedicated for silicon photomultipliers (SiPM) has been designed and developed. While it was designed as a miniaturized and low power device it still provides a wide spectrum of functionality necessary for measurements and testing of SiPMs and SiPM based detectors. Full signal processing has been integrated within the device involving variable gain amplification, filtration and digitization. Signal acquisition can be performed with sampling frequency 400 MSa/s at 12 bit resolution or 600 MSa/s at 8 bit resolution while achieving full waveform capture & download rate about 20 000 events per second. The read-out interface is fully powered from the USB bus allowing operation without need of additional power line connection. An integrated bias source can be set in range from 0V to +200V with 12 bit precision. The read-out interface is primarily dedicated for spectroscopy purposes. There are two input signal channels with different optimization regarding the signal gain to cover a low energy range corresponding to single photo-electron detector response as well as to cover a high energy range corresponding to a detector response operated with scintillator registering gamma radiation in order of MeVs. Both input channels are equipped with fine gain adjustment in range from -9 dB to 26 dB with 1 dB step in addition to the fixed gain of each signal channel. The FPGA based design of the read-out interface allowed implementation of advanced triggering functionality like a data driven trigger, external trigger, gating of trigger to extend read-out interface capability even further in a way of complex experiments. A set of functional tests and experiments with SiPM called micropixel avalanche photodiode (MAPD) and MAPD based detectors have been performed to characterize real properties of the read-out interface.