A method of exposure-dose-rate measurement with a NaI(Tl) crystal

A new method of exposure-dose-rate measurements with a NaI(Tl) crystal has been developed by using an analog-to-digital converter. In order to measure two quantities, i.e. absorption energy rate Esub(ma) and average absorption energy anti Esub(a) in the crystal, a simple measuring method without integrating an energy loss spectrum was used. The non-airlike response of the crystal was corrected by the conversion factor which was determined as a function of average gamma-ray energy anti E, where anti E represented a gamma-ray energy in a place to be measured and which could be easily obtained by the measurement of the average absorption energy anti Esub(a). It has been demonstrated that the present method is useful for the measurement of the exposure-dose-rate at environmental levels. Standard errors of the dose rate measurement for cylindrical NaI(Tl) crystals of 3'' x 3'', 2'' x 2'' and 1'' x 1'' were +- 8%, +- 10% and +- 15%, respectively. (orig.)