Simultaneous retrospective estimation of radiation dose and elapsed time by electron paramagnetic resonance spectroscopy of di-sodium tartrate.

A novel technique for the simultaneous evaluation of the radiation dose and the time elapsed after irradiation is described in detail. The proposed method depends on the use of the two signals of the EPR spectrum of irradiated di-sodium tartrate where they possess different responses towards radiation doses and different behaviors toward the time-dependence of the radiation-induced radicals. An empirical formula was used in order to estimate the radiation dose accurately over the first month following the irradiation process. For the estimation of the elapsed time after irradiation, the ratio of the peak-to-peak intensities of the first peak to the second was used. Uncertainties associated with the estimated elapsed time, U_A(t)_, range from 1.5% to 20.78%, while uncertainties associated with the estimated radiation doses range from 0.26% to 4.53%.