RADIATION DAMAGE STUDIES IN SOLIDS USING THE TECHNIQUES OF ELECTRON-SPIN PARAMAGNETIC RESONANCE AND NUCLEAR MAGNETIC RESONANCE. Annual Progress Report

Technical Report · Thu Mar 01 04:00:00 EST 1962

OSTI ID:4802441

Bray, P J; Williams, Jr, A O; Hooper, H O

Nuelear magnetic resonance (NMR) studies and electronspin paramagnetic rcsonance (ESR) studies were extended in neutron-irradiated LiF with particular attention devoted to the variation of the F-center resonance over the range of neutron doses 10/sup 16/ to 10/sup 19/ nvt and to an examination of the F/sup 19/ molecular gas formation and sodium metal formation from NaF at large neutron doses. The normal F-center resonanee is markedly altered by exchange narrowing when the spin concentration becomes sufficiently high. Measurements of line width and shape, spin-lattice relaxation, spin concentration, and thermal annealing effects are in support of this description of exchange narrowing of the F-center line. The presence of F gas was noted by NMR techniques and the properties of the F/sup 19/ gas resonance were examined as a function of neutron dose. The presence of Na metal in NaF and of Ca metal in CaF/sub 2/ after heavy neutron irradiation was examined in an attempt to determine the mechanisms of metal formation. Final NMR and ESR measurements were made in KBr. Attempts were made to use the experimental data to determine the types and concentrations of the defects produced by neutron irradiation. Calculations of the electric field gradients produced by the defects in the KBr crystals are being carried out. The ESR spectra of atomic H and tritium in neutron-irradtated LiF- single crystals which were annealed were examined at room and liquid N temperatures to determine the trapping sites for these atoms. The Atomic H resonance was observed in annealed neutron-irradiated CaF/sub 2/. The ESR spectra observed in irradiated borate glasses were attributed to a hyperfine interaction of a hole with the B nucleus of a four-coordinated B atom. Investigations of irradiated alkali borate glasses enriched in B/sup 10/ were carried out. ESR spectra were obtained from x ray and neutron-irradiated alumino-silicate glasses. Two types of resonances were observed in the x ray irradiated glasses. The first resonance was attributed to a hyperfine interaction of an unpaired spin with an Al/sup 27/ nucleus of an Al atom bonded in a four-coordinated configuration. The second resonance was attributed to a hole associated with a non-bridging O. A third line observed in the neutronirradiated glasses was identified as the resonance from trapped electrons in the SiO/sub 2/ network. (auth)

• Research Organization: Brown Univ., Providence
• NSA Number: NSA-16-013645
• OSTI ID: 4802441
• Report Number(s): TID-15230
• Country of Publication: United States
• Language: English

Related Subjects

ALKALI METALS
ALUMINUM 27
ALUMINUM SILICATES
ANNEALING
ATOMS
BORATES
BORON
BORON 10
CALCIUM
CALCIUM FLUORIDES
COMPOUNDS
CRYSTALS
DECOMPOSITION
DEFECTS
DISTRIBUTION
ELECTRIC FIELDS
ELECTRONS
ENRICHMENT
FLUORINE 19
GLASS
HEATING
HYDROGEN
HYPERFINE STRUCTURE
INTERACTIONS
LATTICES
LITHIUM FLUORIDES
LOW TEMPERATURE
METALS, CERAMICS, AND OTHER MATERIALS
MOLECULES
NEUTRON BEAMS
NUCLEAR MAGNETIC RESONANCE
POTASSIUM BROMIDES
QUANTITY RATIO
RADIATION DOSES
RADIATION EFFECTS
RESONANCE
SILICON OXIDES
SODIUM
SODIUM FLUORIDES
SPECTRA
SPIN
TRAPS
TRITIUM
X RADIATION