Characterisation and calibration of silicon photomultipliers for next-generation space detectors

A vast range of applications for Silicon Photomultipliers (SiPMs) has already been found in fields such as medical science and industrial applications, to name a few. They are the new photosensors set to replace the traditional photomultipliers for several next-generation space instruments. Owing to their compact size, low cost, excellent time resolution, and high photon detection efficiency, they are currently the most favourable option for space instruments, especially because weight and cost are the fundamental driving factors for sending detectors to space [1]. Apart from employing high-performance SiPMs, it is also important to achieve a convenient trade-off between fast signal processing, good signal amplification, and low noise in order to obtain highquality scientific data. HERD (High Energy Cosmic Radiation Detection facility) is a future spaceborne particle detector that will employ SiPMs for precise charge measurement from Z = 1 to Z = 26 up to a few PeV and gamma identification [2], apart from other scientific objectives. The Plastic Scintillator Detector (PSD), shown in Figure 1, is primarily designed to measure the charge of incoming particles and serve as a veto for gamma-ray selection. Within the scope of this project, the PSD is the primary candidate for SiPM integration. To fully meet the detector’s scientific objectives, optimizing the readout configuration and conducting a thorough characterization of the SiPMs are fundamental tasks, forming the core of this work. This thesis reports the characterisation of Hamamatsu SiPMs - S14160- 3050HS (3x3 mm2) and S14160-1315 (1.3x1.3 mm2) as potential candidates for the PSD readout, in terms of the calibration factor, signal-to-noise ratio, and crosstalk. To achieve this, we first optimized the configuration parameters of the BETA-ASIC, a custom-built front-end readout board designed for SiPMs. This electronics system is characterized by low power consumption, a wide dynamic range, and an excellent signal-to-noise ratio [3]. The Figure 2 shows the BETA-ASIC on the left and the PSD bar equipped with the two different SiPMs on the right. The results from the characterisation of these SiPMs for charge measurement of Low Z and High Z particles in conjunction with the optimised operations of the BETA-ASIC readout board are presented and discussed. Although this work was developed in the HERD project, it can find applications in several high-energy particle detectors.