| Co-Investigator(Kenkyū-buntansha) |
ENDO Yukiko Musashi Institute of Technology, Faculty of Engineering, Assistant Professor, 工学部, 講師 (60287860)
HIRAI Shoji Musashi Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (30112981)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2000: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1999: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1998: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
When γ-rays are counted using a γ-ray spectrometry for neutron activation analysis (NAA), Compton continum from high energy γ-rays often interfers with detection of nuclides with lower energy γ-rays. A coincidence counting of γ-rays in the cascade series with a coaxial Ge detector and a well-type NaI (Tl) detector can reduce this problem.
The coincidence counting method was applied to the determination of Se, Hf, Ba, Cs, Co, Sb, Sc in 4 kinds of certified reference materials (NIES CRM No.16 river sediment, NIES/NIRS typical Japanese diet, NIES/WAMRL fish otolith and JAC0031 river water) and 10 kind of iron remains excavated at the ruins of Kaman-Kalehoyuk in Turkey. These samples and comparative standards were irradiated for 6 h at a thermal neutron flux of 3.7×10^<12> n cm^<-2> s^<-1> in the Rikkyo University Research Reactor (TRIGA Mark-II, 100kW). The irradiated samples were couted by multiparameter MCA (LN-9000, Laboratory Equipment Corporation). A coaxial Ge detector (relative efficiency 21% and FWHM 1.8 keV at 1332 keV) was used for conventional counting method. For coincidence counting method, the coaxial Ge detector and also a well-type NaI (Tl) detector (6 in.φ ×6 in., well 3 in.φ ×4 in.) was used.
Using this method to determine Se, Hf, Ba, Cs, Co, Sb, Sc the lower limit of the determination was improved by 2-4 times compared with the conventional counting method using the coaxial Ge detector.
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