Effects of temperature on cobalt glass dosimeters.

Abstract

The effects of temperature upon the radiation-induced absorbance spectra of cobalt borosilicate glass dosimeters were investigated by subjecting dosimeters to different combinations of preexposure, exposure, and post exposure temperature environments. The dosimeters were exposed to 2 × 104, 105, 5 × 105 and 106R in a 60Co irradiator, and absorbance measurements were taken at 3000 A, 3750 A and 5000 A over a four month study period. No significant difference in absorbance was produced by exposure temperatures within a 0°C to 100°C range, but exposure temperatures beyond 150°C resulted in decreases in absorbance levels. The radiation-induced coloration faded linearly with the logarithm of time following exposure with the fading rates being dependent upon exposure, exposure temperature, storage temperature, and the wavelength at which the absorbance spectra were measured. The coloration was completely removed by a 1 hr heat treatment at 500°C. This clarification treatment did not affect the radiation response of the dosimeters given subsequent exposures.