engleski

Energy dependence of g-values for the purpose of dose reconstruction of soda-lime samples irradiated in a dose range 0.1 – 10.0 Gy

In the field of Electron spin resonance (ESR) dosimetry variety of materials are being investigated for the purpose of dose reconstruction of the victims of radiological and nuclear accidents. One of the desirable properties of ESR dosimeter is energy independence since the radiation accidents are mostly caused by the mixed radiation sources. Soda-lime glass has been proven to be a good ESR dosimeter in the dose range above 2 Gy by using the ESR signal amplitudes, but below 2 Gy the radiation induced signal is overlapping with the intrinsic ESR signal. It was shown [1, 2] that in the range below 2 Gy is possible to reconstruct the dose from the soda-lime glass samples by using the g-value dose dependence of ESR signals. All irradiated soda-lime samples exhibit ESR spectra that can be decomposed to inhomogeneous background signal (BKS) with associated gBKS value, and homogeneous radiation induced signal (RIS) with associate gRIS value. The effective g- value of the irradiated sample is combination of these two. In this study, the dependence of g-effective value on the radiation energy of the ESR signal was investigated. The g-effective value has exponential dependence on the dose as shown before [1, 2]. The samples were irradiated with gamma sources of different energies, X-ray source of energy 39.40 keV and Co-60 source of the mean energy 1.25 MeV in the dose range from 0.1 – 10.0 Gy. All irradiations were performed in IBA Dosimetry Laboratory and the ESR readout was performed on the Bruker Magnettech ESR5000 spectrometer in the Laboratory for Electron Spins Spectroscopy at the Ruđer Bošković Institute. As a conclusion, the preliminary study shown that the g-values of the samples are independent on the energy of radiation source for the energies used in this research.

ESR Dosimetry ; Soda-lime glass ; ESR signal ; g-values ; energy dependence

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