Simulation and Experimental Characterization of the Scintillation Detector for IGOSat

This dissertation describes the work that has been done for the development of the scintillation detector of the IGOSat nanosatellite. Based on the requirements of the project, a concept of the detector has been proposed which required the validation by both simulations and experiments. IGOSat is a university satellite project aimed at developing a nanosatellite containing a scintillator payload that can measure the radiative background in the aurora zones and the South Atlantic Anomaly (SAA) on Low-Earth Orbit. Beside that, the satellite has a GPS Dual-Frequency Payload for measuring the Total Electronics Content (TEC) in the ionosphere. These two payloads are hosted on a 3U CubeSat platform that will be launched on a polar orbit at an altitude of about 650 km. The scintillator payload included a detector which is composed of an inorganic scintillation crystal and five surrounding organic scintillators. The chosen inorganic scintillator is Cerium Bromide (CeBr₃), which is sensitive to both gamma-ray photons and electrons. The five surrounding EJ-200 plastic scintillators, which are mainly sensitive to the electrons, are chosen to discriminate the two types of particles. In other words we can say a particle is a gamma-ray photon when it interacts only in the CeBr₃ crystal, while it is an electron if at least one interaction happened in a plastic scintillator. Monte-Carlo simulations have been used to investigate the detection ability of this detector. A response matrix has been made for the gamma-ray simulation, which can be used to estimate the original energy spectrum of the Low-Earth Orbit gamma-ray photons. An experimental test bench has been set up for measuring the detected spectrum of radioactive sources. These measurements are not only used to validate the simulation results, but also to determine the energy resolution of the detector, and a calibration method for it. A comparison between the Monte-Carlo simulations and the experimental measurements is also provided in this dissertation. Based on the topics described above, the dissertation has 6 chapters as listed below:- Chapter 1 is the introduction to the project and a review of the studies on Low-Earth Orbit radiative background, as well as description on the CubeSat development activities.- Chapter 2 describes the IGOSat satellite configuration on the platform, which is developed to support the payload based on their requirements.- Chapter 3 describes the concept of the scintillation detector, its electronics readout system and the operational concept of the payload.- Chapter 4 explains the physical processes of a particle in the scintillation materials, the Monte-Carlo simulations and the response matrix of the IGOSat detector.- Chapter 5 provides the experimental measurement results, based on each test bench that has been set up. The comparisons between simulation and experiment are also described at the end of this chapter. Chapter 6 is the conclusion of the work. (author)