Evaluation of the thermally and optically stimulated response of an Italian Obsidian irradiated in Co-60 beams

Author(s)

Antonio, Patricia L. ; Oliveira, Raquel A. P. ; Khoury, Helen J. ; Caldas, Linda V. E.

• Document type: Journal article
• Source: Radiation Physics and Chemistry; v. 155, p. 6-pg., 2019-02-01.

Abstract

From Obsidian silicate, in its natural form, pellets were manufactured adding Teflon to the material in powder. These pellets were exposed to the gamma radiation beams of a Co-60 source in a dose interval from 10 Gy to 10 kGy. The Obsidian in powder was investigated in relation to its physical and chemical characteristics, by means of the X-ray diffraction, scanning electronic microscopy and energy-dispersive X-ray spectroscopy techniques. After the irradiation procedure, the signal of the samples was evaluated by means of three techniques: thermoluminescence (TL), optically stimulated luminescence (OSL) and thermally stimulated exoelectron emission (TSEE). The objective of this work was to verify the TL, OSL and TSEE response of the Obsidian + Teflon pellets after exposure to high doses of gamma radiation. Different response characterization tests were performed, as TL and TSEE emission curves, OSL signal decay, reproducibility, dose-response curves, lower detection limits and fading. From these results, it can be observed that the Obsidian + Teflon pellets present good conditions to be used as high dose gamma radiation detectors; the results obtained with the OSL technique were the most adequate in terms of response in function of absorbed dose. The fading of the signals, varying from about 26% (TSEE) to 44% (OSL), in a time interval of 360 h post-irradiation, also showed favorable results for the use of this material as radiation detector, when the measurements are taken after a defined time interval. (AU)

• FAPESP's process: 14/12732-9 - Determination of a reference system and a routine dosimeter using fototransferred luminescent techniques, for high-dose dosimetry in gamma irradiators
• Grantee: Patrícia de Lara Antonio
• Support Opportunities: Scholarships in Brazil - Post-Doctoral