Examination of the wet analysis for the (U-Th)/He method; Attempt to determine the contents of parent nuclides based on the calibration curve method

Fukuda, Shoma   ; Kagami, Saya   

For the determination of parent nuclides in the (U-Th)/He method, the isotope dilution method using U and Th isotope spikes is commonly employed worldwide, and much knowledge has been accumulated. On the other hand, the possession and use of these spikes are strictly restricted, which makes the application of the isotope dilution method itself difficult. After the complete dissolution of apatite and zircon by the wet method, we have therefore attempted to verify the calibration curve method for measuring the concentration of the parent nuclides. Durango apatite and Fish Canyon Tuff zircon, which are well-known as the age standard samples for the fission track method, were used as analytical samples. In this presentation, we will introduce some of the results of the determination of parent nuclides (U, Th, Sm) in each mineral sample based on the calibration curve method as well as results of evaluating the suitable internal standards (Bi, Tl) to determine the contents of parent nuclides.