RADIATION DAMAGE STUDIES IN SOLIDS USING THE TECHNIQUES OF ELECTRON-SPIN PARAMAGNETIC RESONANCE AND NUCLEAR MAGNETIC RESONANCE. Annual Progress Report, May 1, 1963-April 30, 1964

Technical Report · Sun Mar 01 04:00:00 EST 1964

OSTI ID:4085320

Bray, P J; Hooper, H O

The series of potassium halides, KF, KCl, KBr, and W were studied in order to compare the behavior of these compounds when they are subjected to a wide variety of neutron irradiation conditions. Extensive NMR (nuclear magnetic resonance) studies of KBr were carried out since the bromine nuclei serve as sensitive probes detecting changes in the electrical environment of bromine atoms through nuclear electric quadrupole interactions. ESR (electron spin resonance) measurements were also made on these materials, and the results were combined with the NMR results to estimate the rate of atomic displacement during neutron irradiation, the F-center production rate, and the thermal behavior of the defect centers introduced by neutron irradiation. The results indicated that the mean free path of displaced ions, although somewhat temperature dependent, is quite long in these crystals. In addition, the vacancy system induced by the irradiation is apparently produced in clusters. The association of these vacancies to form more complicated defects was found to be influenced rather strongiy by the ambient irradiation temperature. NMR studies of lithium fluoride and lithium bromide were completed. Studies of neutron-irradiated LiF were centered about a careful investigation of the F/sup 19/ NMR line from F/sub 2/ gas produced by irradiation. The chemical shift of this species was accurately determined, and the amount of F/sub 2/ gas produced at several total neutron doses was determined. Results from the NMR study of LiBr were inconsistent as far as a determination of the numbers and types of defects produced in this material by neutron irradiation. Such inconsistences can readily be attributed to variations in temperature and neutron flux for the various samples, all of which were irradiated for different time intervals in the same reactor facility. An NMR study of neutron irradiation effects in NaI single crystals was initiated and extensive pre-irradiation data obtained. Studies of irradiated borate glasses by ESR techniques were extended to glasses of high alkali oxide concentration and to crystalline compounds that exist in the phase-equilibrium diagrams of these alkali-borate systems. From the ESR results an estimate of the approximate value for the density of the boron 2s electron at the site of the boron nucleus was made. The four- and five-line hyperfine structures observed in these borate glasses were examined in detail experimentally in the alkali borate and in the CABRAL glass systems, and the defect centers responsible for these hyperfine structures were identified. The ESR spectra from several alkali borate compounds were compared with the spectra obtained from giasses of similar compositions in order to determine if the same structural units, which were identified by x-ray techniques in the compounds, exist in the glasses. ESR studies of iron group ions in glasses and associated crystalline compounds were initiated. Glasses were doped with Fe/sup 3+/, Mn/sup 2+/, Co/sup 2+/, Cr/sup 3+/ , and Ni/sup 2+/ i ons in an attempt to gain information on the glass structure. In most cases examined to date, additional work will be required in order to determine the exact nature of the site or sites which are responsible for the observed ERS spectra. (auth)

• Research Organization: Brown Univ., Providence
• NSA Number: NSA-18-013842
• OSTI ID: 4085320
• Report Number(s): TID-20296
• Country of Publication: United States
• Language: English

Related Subjects

ALKALI METALS
ATOMIC MODELS
ATOMS
BORATES
BORON
BORON COMPOUNDS
BROMINE
CATIONS
CHEMISTRY
CHROMIUM COMPOUNDS
COBALT COMPOUNDS
CONFIGURATION
CRYSTALS
DECOMPOSITION
DEFECTS
DIAGRAMS
DIFFRACTION
DIFFUSION LENGTH
DISTRIBUTION
ELECTRIC FIELDS
ELECTRON SPIN RESONANCE
ELECTRONS
ENERGY LEVELS
FLUORINE
FLUORINE 19
GASES
GLASS
INTERACTIONS
IRON COMPOUNDS
IRRADIATION
LATTICES
LITHIUM BROMIDES
LITHIUM FLUORIDES
MAGNETIC RESONANCE
MANGANESE COMPOUNDS
MEASURED VALUES
MIXING
MOLECULES
MONOCRYSTALS
NEUTRON BEAMS
NEUTRON FLUX
NICKEL COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
OPERATION
OSCILLATIONS
OXIDES
PHASE DIAGRAMS
PO