Characterisation and Calibration of the Compact High Energy Camera for the Cherenkov Telescope Array

The interaction of very-high energy gamma rays and charged particles, produced in the Universe's most energetic environments, with the Earth's atmosphere produces a cascade of high energy particles. Particles within this cascading shower travel at speeds faster than the speed of light in the atmosphere. As such, the particles emit Cherenkov radiation. Ground based imaging atmospheric Cherenkov telescopes use this phenomenon to observe the particle shower. In doing so, it is possible to determine the direction of the shower and thus the direction of the shower progenitor. This source determination can be used to provide an observation of the environments giving rise to such high-energy photons.

The Cherenkov Telescope Array represents the latest telescope array of this kind and will provide highly sensitive observations of gamma rays ranging in energy from 20GeV to 300TeV with the use of three telescope sizes. CHEC-S is one of the Cherenkov imaging cameras proposed for the Small Sized Telescope. It is a compact imaging camera that is designed to be used with a dual-mirror Schwarzschild-Couder design telescope. In addition to this novel telescope design, CHEC-S will utilise silicon photomultipliers for the detection of Cherenkov light in conjunction with an updated iteration of front end electronics based on the TARGET ASIC.

In this thesis, relevant tasks completed for the comissioning of CHEC-S is presented. In addition, the calibration of the TARGET-C digitising ASIC is outlined with a discussion on performance. A proposed change to the calibration method and enhanced performance is given. Finally, the results of the on-telescope campaign of CHEC-S is presented, highlighting the requirement for the method outlined in this thesis for the correction of TARGET-C saturation.