| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Sources of ^<80,80m>Br and ^<105>Ru were produced by thermal neutron irradiation of enriched Na^<79>Br (enrichment:99.41%) and ^<104>Ru (99.21%) metal powder at KURRI. Sources for absolute measurement were prepared on metallized VYNS films from HCl solution containing the suspended powder, and the disintegration rates and the γ-ray intensities were measured by a 4πβ-γ(HPGe) coincidence apparatus using a two-dimensional data-acquisition system. The γ-ray detection efficiencies for the HPGe detector were calibrated in each series of measurements by standard sources of ^<24>Na,^<57>Co,^<60>Co,^<133>Ba,^<134>Cs and ^<152>Eu. These sources were prepared from radioactive solution and measured by the same apparatus.
The internal conversion electrons from ^<80m>Br (4.42 h) affect for disintegration rate measurement of ^<80>Br (17.68 m), and the β-rays from ^<24>Na (14.965 h) are also counted in the 4πβ-counter. On the other hand, ^<105>Rh, daughter of ^<105>Ru, decays by β-particle emission with half-life of 35.36 h. Therefore, it was necessary various attention in the measurements and data treatments.
The γ-ray emission probability of 616.3 keV for ^<80>Br was 6.14±0.05% and the previously reported value of 6.7±0.6% were larger by about 10%. The data for ^<105>Ru were in agreement with the evaluated values within the uncertainties, but uncertainties were greatly improved from 3% to 0.6% for intense γ-ray. On the other hand, those of 306.1 keV and 318.9 keV for ^<105>Rh were 4.76±0.05% and 16.99±0.17% and the evaluated values of 5.1±0.6% and 19.1±0.6% were larger by about 10%.
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