Examination of color center formation in CaF2 crystals when exposed to gamma and mixed neutron/gamma fields

Author

Sara M. Pelka, University of New MexicoFollow

Publication Date

Summer 7-13-2017

Abstract

Color centers in CaF₂ were studied in this work, in parallel with examinations of changes in the refractive index of the crystals by the larger research group, after they were subjected to radiation. Color centers induced by gamma rays and in mixed neutron-gamma fields were studied in CaF₂ and LiF using transmittance and absorbance spectra. The goals were to examine both neutron and neutron-gamma mixed field irradiations to be able to isolate neutron only effects and to correlate these color center effects with refractive index effects studied by our larger collaboration. Irradiation sources include ¹³⁷Cs, DD and DT reactions at Sandia National Laboratory, the University of New Mexico Neutron Howitzer, and the Oregon State University TRIGA reactor. Only the samples irradiated to high doses, 2.176x10⁵ Gy through 2.176x10⁷ Gy, at Oregon State University showed strong color centers. Different color centers had different intensities and the absorbance as a function of dose shows a clear relation and is dependent on the specific color centers. UV bleaching shows a similar relation in reverse.

Keywords

color center, material damage, CaF2, neutron damage, gamma damage, F center

Document Type

Thesis

Language

English

Degree Name

Nuclear Engineering

Level of Degree

Masters

Department Name

Nuclear Engineering

First Committee Member (Chair)

Dr. Adam Hecht

Second Committee Member

Dr. Gary Cooper

Third Committee Member

Dr. Cassiano De Oliveira

Recommended Citation

Pelka, Sara M.. "Examination of color center formation in CaF2 crystals when exposed to gamma and mixed neutron/gamma fields." (2017). https://digitalrepository.unm.edu/ne_etds/61