Dosimetric properties of AL2O3:C, Mg exposed to external cobalt-60 gamma irradiation

Abstract

This study concerns on the thermoluminescence properties of Al2O3:C, Mg exposed to cobalt-60 gamma rays. The thermoluminescence properties investigated were thermoluminescence glow curve, linearity, sensitivity, fading, reproducibility, minimum detactable dose, energy response and thermoluminescence parameters. The samples were supplied by Testbourne Ltd, England in the form of sputtering target and the samples were crushed into powder form with grain size of 75 µm to 200 µm. The crystalline phase of the samples was identified using X-ray diffraction analysis. The results indicated that the powder samples are in polycrystalline state. Thermoluminescence properties were investigated by irradiating the samples to cobalt-60 gamma ray with doses from 5 Gy to 70 Gy. The glow curves were analyzed to determine various thermoluminescence properties of the samples. The results clearly show that Al2O3:C (0.2%), Mg (0.2%) has better thermoluminescence properties in terms of sensitivity, linearity, reproducibility and fading compared to other samples. Zeff of the samples were calculated as 10.83±0.01 and the results are close to Zeff of bone. The total mass absorption coefficients of Al2O3:C (0.2%) and Al2O3:C (0.2%), Mg (0.2%) were calculated using WinXCom software in order to calculate the photon energy response of the samples. By using the trumpet graph, the values of R (Dmeasured / Ddelivered) for Al2O3:C (0.2%), Mg (0.2%) sample were within the acceptable limit recommended by ICRP. The average activation energy of Al2O3:C (0.2%) and Al2O3:C (0.2%), Mg (0.2%) were calculated as 2.03 eV and 1.49 eV, respectively. The frequency factor calculated from TL glow curves of Al2O3:C (0.2%) and Al2O3:C (0.2%), Mg(0.2%) were 2.61x10(25)s(-1) and 7.51x10(17)s(-1), respectively.