Влияние γ-облучения на полупрозрачный обсидиан серого цвета в области доз от 5 до 500 кГр

Abstract

Semitransparent gray color obsidian samples (bulk and powder) were irradiated at room temperature by Co60 radiation source with the γ-photon average energy of 1.25 MeV and with different doses from 5 to ~500 kGy. It is known that γ-irradiation influences on the optical properties of glass materials depending on the composition as well as due to the presence of defects in the glass matrix. Analysis of obsidian samples were carried out by the absorption and reflection spectroscopy in the UV, visible and IR ranges, as well as EPR measurements for characterization of semitransparent gray color obsidian depending on the γ-irradiation different doses. The difference transmittance spectra between the pristine sample and those irradiated with different doses made it possible to distinguish three absorption bands at 368, 386, and 442 nm, which are responsible for Fe3+ ions in different environments. The content of hydroxyl OH groups, determined from the absorption in the band at ~4500 cm–1, does not change in the range of used doses. EPR measurements showed three signals with g-factors of ~6.0, ~4.2, and ~2.0 characteristic for Fe3+ ions, the intensities of which increase with increasing irradiation doses. Obsidian turned out to be resistant to the formation of NBOHC paramagnetic defects in the region of the indicated doses of γ-irradiation.