1. Scintillation Materials Research Center, University of Tennessee, Knoxville, Tennessee 37996, United States
2. Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
3. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
4. Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States