Spectral determination method and its application to γ-ray determination

We propose a simple algorithmic method of spectral determination method (SDM) for γ-ray determination, which is based on the first principle that a γ-ray spectrum obtained for a sample is a linear superposition of individual spectra of the radioactive nuclides included in the sample. The SDM treats the whole spectrum including peaks and a continuum background due to Compton scattering and does not need the peak analysis, which has been most conventionally used so far. The SDM was demonstrated by using two separate detector setups with a NaI detector or a Ge detector. The first experiment utilized six mixed standard sources. The determination accuracy of the SDM has turned out to be reasonable as compared with that of the peak analysis. In the next experiment for standard samples of JSAC0731 and JSAC0785, both Ge and NaI results show that the deviation of the SDM results from the certified values is within reasonable uncertainties for 137C and 134Cs. The present study demonstrates that the SDM is a reliable γ-ray determination method with a simple procedure.