RADIATION-INDUCED DILATATIONS IN VITREOUS SILICA

Journal Article · Sat Dec 15 04:00:00 EST 1962 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.128.2580· OSTI ID:4740584

Primak, W; Edwards, E

It is shown that when vitreous silica is irradiated in a nuclear reactor, three effects cause dimensional changes: a homogenization effect assigned to fast neutrons (period approximates 3 x 1020 nvt), a compaction (about 3%) assigned mainly to fast neutrons (period approximates 3 x 10/sup 19/ ), and a dilatation caused by ionization. The ionization-induced dilatation is negative at the beginning of the irradiati on, but becomes positi ve after a brief irradiation. It probably is responsible for the positive dilatation which occurs after the maximum compaction. Most specimens show internal stresses which give evidence of nonuniform effects. The cause is a radiation gradient due to absorption and/or scattering of the radiation in the specimen. In the period of rapid compaction the strain shows one sign, reaches a maximum, then goes to zero near the maximum in the compaction, and changes sign in the period of expansion. The strain does not seem to saturate when the dilatation saturates. The deformation of the specimens is of the order of magnitude expected from the internal stresses. A thermal effect like a radiation annealing was found in the region between room temperature and 90 deg C. Results obtained from irradiations by x rays, electrons, as well as by mixed radiation in a nuclear reactor are reported. Because of the concomitant ionization effect it was not found possible to determine the displacement threshold energy by electron bombardment. The ionization effects are taken as evidence of electrostatic effects in the radiation-induced dilatations of silica. However, the electrostatic effects cannot account for all of the volume changes observed in the irradiation of vitreous silica. (auth)

• Research Organization: Argonne National Lab., Ill.
• NSA Number: NSA-17-005016
• OSTI ID: 4740584
• Report Number(s): TID-15848; 0031-899X
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 128; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ABSORPTION
ANNEALING
DEFORMATION
ELECTRONS
ELECTROSTATICS
EXPANSION
FAST NEUTRONS
GLASS
IONIZATION
IRRADIATION
METALS, CERAMICS, AND OTHER MATERIALS
RADIATION EFFECTS
REACTORS
SCATTERING
SILICON OXIDES
STRESSES
X RADIATION