Front-End Electronics for Silicon Photomultipliers

Nowadays, detection of low-light levels is required in several application fields, including high-energy and astroparticle physics, medical imaging, and material science, just to mention a few. Calorimetry and positron emission tomography (PET) are among the most common examples of these kinds of applications, which call for the availability of detectors featuring some form of internal charge multiplication mechanism, especially when single-photon sensitivity is required. In the past, photomultiplier tubes (PMTs) and avalanche photodiodes (APDs) have been the detectors of choice to fulfill such requirements, thanks to their excellent characteristics in terms of gain and time resolution. The advent of single-photon avalanche photodiodes (SPADs) operated in Geiger mode paved the way to the introduction of silicon photomultipliers (SiPMs), which offer several advantages over the competitor detectors [1–5]. Low-voltage operation, compactness, ruggedness, and low cost make SiPMs an interesting solution in a broad range of applications and experimental environments. Availability in different pixel numbers and sizes and easy customization guarantee SiPMs’ high flexibility and adaptability to a large variety of situations. Furthermore, insensitivity to magnetic fields extends their possible use to frontier applications, such as positron emission tomography–magnetic resonance imaging (PET-MRI) instrumentation. Thanks to the growing interest in, and the diffusion of, these kinds of detectors, increasing research efforts have been dedicated to the development of the related technology, thus allowing, on the one hand, further improvements of the performance 204in terms of gain, photon detection efficiency, and timing resolution and, on the other hand, mitigation of the main drawbacks that characterize the behavior of SiPMs [6].