Characterisation of Silicon Photomultiplier Detectors for their Application in Very-High-Energy Astrophysics.

A novel method has been developed in this thesis to characterise silicon photomultiplier (SiPM) detectors for their application in very high energy astrophysics. This method includes a novel technique to digitally shape and filter SiPM pulses, that allows the extraction of a clean SiPM pulse. A transfer function has been developed using the Laplace Transform in the s-plane on the equivalent electrical circuit model of an SiPM. This transfer function allows easy extraction of all the electrical parameters of an SiPM. This method has then been used to investigate four novel SiPMs for their primary application in the Compact High Energy Camera (CHEC-S) designed for the upcoming next generation ground based gamma ray observatory Cherenkov Telescope Array (CTA). Another novel technique has been developed to investigate the thermal response of an SiPM. This method accurately probes the junction temperature of an SiPM when it is exposed to varying levels of night sky background (NSB). Finally, a simulation called Toy Model has been developed to simulate the impact of SiPM parameters such as pulse shape and gain on the trigger level, efficiency and resolution of CHEC-S.