Inorganic scintillators are widely used in various gamma spectroscopy applications such as nuclear nonproliferation and safeguards, medical applications, space applications, and astronomy. They typically have good energy resolution, stable performance, low cost compared to semiconductors, and high detection efficiency. However, many inorganic scintillators have high refractive indices and suffer significant light losses due to total internal reflection (TIR). These TIR losses can be reduced by modifying the boundary conditions at the scintillator-photosensor interface. We have been assessing the use of periodic arrays of dielectric nanostructures termed photonic crystals (PHCs) to improve the overall light extraction via constructive interference. Our earlier simulation work has demonstrated that the use of 2D PHCs for LYSO and BGO 10 x 10 x 3 mm3 scintillators should improve the light extraction by more than 60% and 90%, respectively. These simulations were done with OptiFDTD code only for a single light pass through the scintillator. Future work will include multiple light passes, allowing for even more realistic simulations. In this work, we manufacture an unoptimized PHC geometry and characterize it with radiation measurements. The manufacturing process needs to be optimized for the small PHC dimensions we require for optimized PHC production. Future work will focus on building a reliable and consistent manufacturing process that allows us to validate our model and assess the full potential of optimized PHC structures in improving the detector’s performance and energy resolution. A validated simulation model will also allow us to estimate the PHC capabilities of other inorganic scintillators, such as sodium iodide and lanthanum bromide.
Year
2024
Abstract