NE Colloquium: Luis Stand
Title: "Crystal Growth and Characterization of Selected High-Performance Scintillators for National Security Applications."
Scintillators are important materials for radiation detection applications such as homeland security, geological exploration, and medical imaging. Scintillators for nuclear nonproliferation applications in particular must have excellent energy resolution in order to distinguish the gamma-ray signatures of potentially dangerous radioactive sources, such as highly enriched uranium or plutonium, from non-threat radioactive sources such as radioactive tracers used in medical imaging. There is an established need for scintillators with energy resolution in the 1-2% range at 662 keV. However, there are challenges surrounding the development of this new generation of high light yield/high resolution scintillators; for example, the high cost of production due to low crystal yield and slow growth process, and crystal inhomogeneity. We will discuss efforts focused on developing recently discovered high performance scintillators K(Sr,Ba)2I5:Eu, LiSr2I5(Eu), Cs4(Ca,Sr)I6:Eu and Cs2Hf(Cl,Br)6 that have potential for meeting nuclear security needs. Growth parameters for these materials have been optimized, allowing the growth of excellent quality single crystals measuring up to one-inch in diameter via the vertical Bridgman technique at translation rates between 0.2 and 5 mm/h. These scintillators have excellent properties with light yields between 30,000 and 120,000 ph/MeV, and energy resolutions between 2.0 and 4.6% at 662 keV. To thoroughly understand the scintillation mechanism of these materials, we also investigated other fundamental properties such as the electron response (SLYNCI) and thermoluminescence to determine whether charge traps affect their proportionality and scintillation kinetics.
Luis Stand received his PhD in Energy Science and Engineering in 2018 from the Bredesen Center at UT, where he specialized in the crystal growth and characterization of scintillator materials for radiation detection applications. He is now a post-doctoral research associate in the Scintillation Material Research Center at UT, where he discovers and develops new scintillator materials for medical imaging and national security applications. Stand currently has 40+ publications, and at this time holds ten issued patents, with several additional US patent applications pending. He has been, among other things, the driving force behind the invention and development of the new scintillator, europium doped KSr2I5 – an exceptionally proportional, high light yield scintillator with some of the best energy resolution ever measured in a scintillator.
Zoom Meeting ID: 92048071278
Thursday, May 13 at 3:00pm to 4:00pmVirtual Event