Experimental Results from an Analog Front-End Channel for Silicon Photomultiplier Detectors

Silicon photomultipliers (SiPM) have rapidly increased their popularity among scientists and engineers involved in the detection of low energy photons over a wide range of applications, thanks to their characteristics which compare favourably with those of photomultiplier tubes (PMT), in terms of bias voltage, immunity to magnetic fields and size. Their high speed of operation and their wide dynamic range call for the development of dedicated front-end electronics. In particular, in the perspective of very deep sub-micron CMOS technologies with reduced supply voltages, serious restrictions affect the traditional voltage mode front-end used for particle detectors, due to the huge values of the integration capacitance needed in the Charge Sensitive Amplifier (CSA). Recently, a novel current-mode front-end architecture has been presented which uses an enhanced current follower as a first stage and includes also some programmable features to cope with the needs of a variety of different applications. Here, we report and discuss the first experimental results referring to a single-channel prototype, designed in a standard 0.35μm CMOS technology, coupled to a SiPM excited by a blue LED light source. The results confirm the effectiveness of the proposed current-mode approach. In particular, charge measurements are in good agreement with the predicted values of the total charge released by the SiPM in response to a light source, for various bias conditions.