Simulation and Characterization of Single Photon Detectors for Fluorescence Lifetime Spectroscopy and Gamma-ray Applications

Gamma-ray and Fluorescence Lifetime Spectroscopies are driving the development of non-imaging silicon photon sensors and, in this context, Silicon Photo-Multipliers (SiPM)s are leading the starring role. They are 2D array of optical diodes called Single Photon Avalanche Diodes (SPAD)s, and are normally fabricated with a dedicated silicon process. SPADs amplify the charge produced by the single absorbed photon in a way that recalls the avalanche amplification exploited in Photo-Multiplier Tubes (PMT)s. Recently 2D arrays of SPADs have been realized also in standard CMOS technology, paving the way to the realization of completely custom sensors that can host ancillary electronic and digital logic on-chip. The designs of scientific apparatus have been influenced for years by the bulky PMT-based detectors. An overwhelming interest in both SiPMs and CMOS SPADs lies in the possibility of displacing these small sensors realizing new detectors geometries. This thesis examines the potential deployment of SiPM-based detector in an apparatus built for the study of the Time-Of-Flight (TOF) of Positronium (Ps) and the displacement of 2D array of CMOS SPADs in a lab-on-chip apparatus for Fluorescence Lifetime Spectroscopy. The two design procedures are performed using Monte-Carlo simulations. Characterizations of the two sensor have been carried out, allowing for a performance evaluation and a validation of the two design procedures.