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Title: Linearity for Ca2+-Doped CeBr3 Scintillating Materials

The Remote Sensing Laboratory (RSL) developed an aliovalently calcium-doped cerium tribromide (CeBr3:Ca2+) crystal with 3.2% resolution. RSL completed a crystal assessment, and Sandia National Laboratories calculated the predictive performance and physical characteristics using proven density functional theory (DFT) formalism. Results are reported for the work done to map the detector performance, characteristics, calcium doping concentration, and crystal strength. Preliminary scintillation measurements for this aliovalently calcium-doped CeBr3 scintillator exhibit a slight blue shift in fluorescence emission at 371 nm excitation for CeBr3. The structural, electronic, and optical properties of CeBr3 crystals were investigated using DFT within generalized gradient approximation. The calculated lattice parameters are in good agreement with the experimental data. The energy band structures and density of states were obtained. The optical properties of CeBr3, including the dielectric function, were calculated. Specifically, we report excellent linearity with the aliovalently calcium-doped CeBr3 crystal. Proportionality of light yield is one area of performance in which Ce-doped and Ce-based lanthanide halides excel. Maintaining proportionality is key to producing a strong, high-performance scintillator. Relative light yield proportionality was measured for both doped and undoped samples of CeBr3 to ensure no loss in performance was incurred during doping. The light output and proportionality, however, appearmore » to be similar to CeBr3. There was a reduced yield at low energy. Relative light yield proportionality measurements suggest that dopants do not significantly affect proportionality at higher energies. RSL completed additional testing and evaluation of the new crystal and assessed benchmark spectroscopy measurements. Results, which present energy resolution as a function of energy, are summarized. Typical spectroscopy results using a 137Cs radiation source are shown for our crystallite. We obtain 4.5% for the packaged crystallite. More spectra are presented for 241Am, 60Co, 228Th, and background to exemplify CeBr3:Ca2+ over a broader energy range.« less
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Conference: 2014 Symposium on Radiation Measurements and Applications (SORMA XV) June 9-12, 2014, University of Michigan - Ann Arbor
Research Org:
Nevada Test Site/National Security Technologies, LLC (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY detector, resolution, scintillator materials, gamma-ray detector, cerium tribromide; CeBr3; high-resolution detector; halides; rare-earth compounds; scintillator; gamma spectral comparison; resolution; aliovalent substitution