Event Details

Join Professor Marek Flaska of Pennsylvania State University for a talk on radiation detection.

This talk will consist of two parts. The first part will provide a high-level overview of U.S. activities in the field of nuclear energy, while the second part of the talk will focus on inorganic scintillation detectors used for gamma-ray counting and energy spectroscopy. Inorganic scintillators are widely used for various radiation detection applications, including nuclear nonproliferation and safeguards, medicine, space exploration, and fundamental physics. 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. 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). Improving the LO of an inorganic scintillator leads to enhanced energy and time resolution, which in turn allows for an extended range of radiation detection applications for inorganic scintillators. 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 substantially 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.

Marek Flaska is an assistant professor in the Ken and Mary Alice Lindquist Department of Nuclear Engineering at Pennsylvania State University. His research focuses on designing radiation detection systems for nuclear non-proliferation, safeguards, forensics, and fundamental physics applications.

Marek received his B.Sc. and M.Sc. in nuclear engineering from Slovak Technical University; he earned his PhD. in applied physics from the Delft University of Technology, then completed a postdoctoral appointment at Oak Ridge National Lab. He was an associate research scientist at the University of Michigan.

This talk will be of interest not only to staff and students in Engineering and Nuclear, but also to colleagues and students in Chemistry and Physics with an interest in inorganic nanoscale materials for nuclear applications.