Year
2022
Abstract
Inorganic scintillation-based detectors are widely used for gamma spectroscopy due to their high light yields providing reasonable energy resolution at a relatively low cost. Despite high light yield from inorganic scintillators, a significant fraction of the light is lost at the scintillator and photodetector interface due to total internal reflection in the crystal. The optical interface between the scintillator and the light sensor can be engineered to reduce the fraction of light lost to total internal reflection. This project aims to use 2-D nanostructures to build an optical bridge between the scintillator and the light sensor, allowing enhanced light transmission. These nanostructures termed “photonic crystals” can have optimized geometries for various scintillator materials to yield the best light output. The optimization of 2-D photonic crystals is carried out using a deterministic code that calculates light wave propagation by solving Maxwell’s coupled curl equations employing the finite-difference time-domain method. Using UV-Vis experimental data, the simulation model is first validated for 87 nm and 600 nm TiO2 films and 360 nm Si3N4 film. The model is then used to simulate Si3N4 nanostructures optimized for coupling with a LYSO scintillator. The optimized geometries will be manufactured and characterized using various gamma sources. It is hypothesized that a significant improvement in light collection and energy resolution will be observed.