The silicon photomultiplier: fundamentals and applications of a modern solid-state photon detector

Abstract

The silicon photomultiplier (SiPM) is an established device of choice for a variety of applications, e.g. in time of flight positron emission tomography (TOF-PET), lifetime fluorescence spectroscopy, distance measurements in LIDAR applications, astrophysics, quantum-cryptography and related applications as well as in high energy physics (HEP).To fully utilize the exceptional performances of the SiPM, in particular its sensitivity down to single photon detection, the dynamic range and its intrinsically fast timing properties, a qualitative description and understanding of the main SiPM parameters and properties is necessary. These analyses consider the structure and the electrical model of a single photon avalanche diode (SPAD) and the integration in an array of SPADs, i.e. the SiPM. The discussion will include the front-end readout and the comparison between analog-SiPMs, where the array of SPADs is connected in parallel, and the digital SiPM, where each SPAD is read out and digitized by its own electronic channel.For several applications a further complete phenomenological view on SiPMs is necessary, defining several SiPM intrinsic parameters, i.e. gain fluctuation, afterpulsing, excess noise, dark count rate, prompt and delayed optical crosstalk, single photon time resolution (SPTR), photon detection effieciency (PDE) etc. These qualities of SiPMs influence directly and indirectly the time and energy resolution, for example in PET and HEP. This complete overview of all parameters allows one to draw solid conclusions on how best performances can be achieved for the various needs of the different applications.

Exploring Cherenkov Emission of BGO for TOF-PET

“…A time resolution degradation of 8 % (160 ± 3 ps → 173 ± 3 ps) for FBK and up to 26 % (236 ± 7 ps → 298 ± 7 ps) for Ketek compared to the results for smaller cross section is observed. One part of this deterioration comes from light loss at the edges of the crystal, as some light can escape and is not detected [21]. In addition there can be some light loss for crystals being not perfectly aligned, a combination of vertical and horizontal displacement of 0.2 mm would lead already to a light loss of ≈15 %.…”

Medical Physics and Imaging–A Timely Perspective

“…Recent examples of these engagements in research and development of imaging systems include the introduction of solid-state based photo-detectors [24], the design and validation of a total body PET system [25], a novel PET system based on plastic scintillators (J-PET) and Compton cameras [26]. Further, progress was made, for example, with the introduction of MR-based attenuation correction for PET/MRI systems, Monte Carlo based scatter correction methods and advanced reconstruction algorithms for SPECT and PET.…”

Fully digital PET is unaffected by any deterioration in TOF resolution and TOF image quality in the wide range of routine PET count rates

“…While both Siemens and GE PET/CT scanners use analog SiPMs (aSiPM), the Vereos PET/CT use a detection system based on digital SiPMs (dSiPM) with the particularity that each Single Photon Avalanche Diode (SPAD) is connected to its own readout electronics [20,21]. Currently, aSiPM and dSiPM have comparable performances with regard to TOF resolution [22], although the latter is expected to better prevent electronic-and detector-related noise [23][24][25][26]. When compared to aSiPMs, dSiPMs have active quenching/recharge mechanisms, a property that usually leads to enhanced count rate stability and shortened dead times [23].…”