Optimization of dental enamel EPR dosimetry spectra measurements parameters

Abstract

Optimization of parameters for measuring spectra for EPR spectroscopy by tooth enamel was performed with the aim of increasing the accuracy of the method. The uncertainty of the dose determination is directly measured as the mean square deviation of the experimental doses from the nominal doses at different microwave power and the time of measurement of the spectra for ten samples of enamel irradiated in the range from 0 to 500 mGy. The measurements were carried out for the JEOL JES-FA100 spectrometer operating in the Xband and equipped with a cylindrical resonator ES-UCX2 with a high Q factor of the TE011 regime at the University of Hiroshima. Measurements of the samples were carried out at the same measurement parameters, but at different powers of microwave radiation (SHF), as well as for different accumulation times of the spectra. The minimum uncertainty was reached at a microwave power of about 2 mW. To determine the optimal conditions for recording the spectra, direct measurements of the parameters SDS and SDR were carried out. When the total measurement time is set, a lower uncertainty is obtained if we take the average value of the experimental doses obtained from several repeatedly measured spectra after shaking the sample and rotating the tube than from one spectrum recorded at a longer accumulation time.