P&A Colloquium – Dr. Marek Flaska, Pennsylvania State University
Oct 1, 2025
10:30AM to 11:30AM
Date/Time
Date(s) - 01/10/2025
10:30 am - 11:30 am
BSB 108
Dr. Marek Flaska
Associate Professor
The Pennsylvania State University
Profile: https://www.nuce.psu.edu/department/directory-detail-g.aspx?q=MXF5309
TITLE: Repetitive-Nanostructure Coating for Inorganic Scintillators for Superior Timing and Energy-Resolution Performance
ABSTRACT:
Inorganic scintillators are widely used in various applications of gamma counting and spectroscopy, such as nuclear nonproliferation and safeguards, and medical, space, or industrial applications. Typically, they have a good energy resolution, stable performance, somewhat low cost, and relatively high gamma detection efficiency. However, many inorganic scintillators have high refractive indices and therefore suffer from significant light losses due to the light phenomenon called the total internal reflection (TIR). This research project investigates using optimized, two-dimensional, periodic nanostructures called photonic crystals (PHCs) to aid in recovering some of the TIR-driven light loss. From the practical point of view, PHCs can create, via constructive interference of electromagnetic light waves, an improved optical coupling between a scintillator and photosensor for the trapped light, thereby improving the overall light extraction, collection, and consequently the light output (LO) of the scintillator-photosensor assembly. Improving the LO of an inorganic scintillator leads to enhanced energy and time resolutions, thereby allowing for an extended range of radiation detection applications. LYSO scintillator was chosen for the initial PHC-coating efforts because it has higher light yield and energy resolution than BGO while being hygroscopic, which simplifies the PHC-manufacturing process. A PHC-coating method was developed for the LYSO scintillation material with Si3N4 through the e-beam lithography and ion etching. The radiation measurements show a LO improvement of up to 28% and up to 13% in energy resolution for the best performing PHC coating for 10 x 10 x 3 mm3 LYSO scintillators. Future work will include further improving the overall quality of the manufactured PHCs and incorporating experimentally observed defects in tailored simulations. In addition, the existing manufacturing process will be modified for different scintillator materials, including BGO, NaI, and LaBr3.