초록
In this study, the mass attenuation coefficients for all five of the IAEA reference material samples(apparent density in a measuring bottle: $0.50{\sim}1.45g{\cdot}cm^{-3}$), including soil, milk powder, hay and moss soil, were determined using the CT (Calibration Transmission) method. A certified mixed gamma-ray sources including $^{241}Am$, $^{88}Cd$, $^{57}Co$, $^{113}Sn$, $^{85}Sr$ and $^{137}Cs$ were added to the IAEA reference samples for the validation of present method. The self-attenuation correction factors for the gamma-ray energies of 59.5 keV, 88 keV, 122.1 keV, 391.7 keV, 514 keV and 661.7 keV were determined and applied to the self-attenuation correction. As a result, the accuracy of gamma-ray spectrometry for environmental samples used in this study was improved especially for lower energy gamma-ray emitting radionuclides.