When radiation facility for various unsealed radioisotopes intends to execute clearance of solid waste contaminated by only short half-life nuclide, a necessary strategy to prevent from contamination of long half-life nuclide has been shown in technical examination interim. We established our radiation facility as a model for classification management of nuclide according to length of half-life and examined the effectiveness of the classification management of the interim report as index nuclides, tritium and Phosphorus-32, based on the example of our classification management of the nuclide in facilities. In this report it was found that the classification management of the nuclide by half-life prevented effectively long half-life nuclide from mixing with the solid waste contaminated by only short half-life nuclide.
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 (Emax). On the other hand, the end points of the spectra of 14C and 35S showed their Emax, 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.
Zinc Oxide (ZnO) family phosphors as phosphor for neutron detector have prepared using Spark Plasma Sintering (SPS) method. The optical properties of ZnO phosphor prepared are investigated. The following results were obtained. Two dominant photoluminescence (PL) emission peaks at 395 nm and 495 nm were observed. The lifetime of the PL emission peak at 395 nm (UV emission band) is about 20 ns, which is suitable for neutron detection. The Ga (30 mol%)-doped ZnO phosphor exhibited an intense UV emission band without the visible emission band. The Ga-doped ZnO phosphor can be prepared at the atmospheric pressure of about 8 Pa using SPS method. It was found that the PL intensity of UV emission band is increased with improving the crystallinity of the ZnO phosphor.