Identification for pure-beta nuclides of ¹⁴C and ³⁵S with plastic scintillator applied to conventional liquid scintillation counter

Spectra for pure-beta nuclides with liquid scintillator by using a liquid scintillation counter (LSC) are usually shifted to low energy region caused by optical and chemical quenching processes. So the end-point of LSC spectrum does not show the theoretical maximum beta-ray energy (E_max). On the other hand, the end points of the spectra of ¹⁴C and ³⁵S showed their E_max, when a plastic scintillator (PS) was used for measurement as a substitute for a liquid scintillator. Therefore, the possibility of identification of ¹⁴C and ³⁵S with plastic scintillator applied to conventional liquid scintillation counter is the aim of this study. Spectra could be measured with good reproducibility. Moreover the reusability of the PS rinsed within a day or covered with a thin film was also confirmed. (author)