RADIOISOTOPES
Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
Volume 64 , Issue 12
Showing 1-7 articles out of 7 articles from the selected issue
Article
  • Naoyuki KANDA, Ying WANG, Noriaki KATAOKA, Ryuta YAMADA, Hiroshi IMAIZ ...
    2015 Volume 64 Issue 12 Pages 717-728
    Published: December 15, 2015
    Released: December 29, 2015
    JOURNALS OPEN ACCESS
    The Fukushima Daiichi Nuclear Power Plant Accident happened in 12 - 15th March 2011. This accident caused to the radioactive contamination in the near area. In this work, some lake waters and the sediments were collected in Fukushima Prefecture and Niigata City to clarify the effect of the accident on the area contaminated. As to the collected lake water, an enrichment of “the specific activity of tritium(T specific activity)” in each water collected was carried out by the solid polymer electrolyte(SPE) apparatus, and the T specific activity was measured by a liquid scintillation counter. Based on the T specific activity thus measured, the influence of the accident to the environment was investigated. At the same time, specific activities of radioactive caesiums in the lake sediments were also measured. Consequently, the influence of the Fukushima Daiichi Nuclear Power Plant Accident to the adjacent lakes(e.g., in Fukushima Prefecture and Niigata City) was quantitatively clarified. From the above‐mentioned matters, it is found that the effect of the accident on Niigata City is so small, and the accident gradually decreases in Fukishima Prefecture.
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  • Xiaosong Xiaosong, Yang TIAN, Kenji SHIMAZOE, Takeshi FUJIWARA, Hiroyu ...
    2015 Volume 64 Issue 12 Pages 729-735
    Published: December 15, 2015
    Released: December 29, 2015
    JOURNALS OPEN ACCESS
    A high-energy X-ray/gamma-ray imaging system based on a hydrogenated amorphous silicon(a-Si:H)/crystalline silicon(c-Si) heterojunction strip detector was developed. The imaging system will be applied in nondestructive testing of concrete structures. We fabricated 50-channel heterojunction strip detectors with a1mm pitch on 500μm thick p-type silicon wafers. The average leakage current was 2.9nA per channel at 120V reverse bias. Energy resolutions of 2.8keV FWHM at 59.5keV and 2.9keV FWHM at 122keV were obtained at 18. The position sensitivity of the strip detector was measured by edge-on irradiation with a 137Cs gamma-ray source. Edge-on gamma-ray imaging of a tungsten object using the prototype was performed. A module consisting of 20 stacked silicon strip detectors is being constructed.
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Technical Report
  • Takao KAWANO, Yoshiaki ANDO, Yuuichi IZUMI
    2015 Volume 64 Issue 12 Pages 737-744
    Published: December 15, 2015
    Released: December 29, 2015
    JOURNALS OPEN ACCESS
    Instant coffee contains natural potassium-40 and is a very comprehensible educational tool for illustrating naturally existing radiations and radioisotopes because potassium-40 emits radiations. In the present study, a compression and formation method was applied to 10 varieties of commercially available instant coffees and 10 coffee block radiation sources were fabricated. Thus fabricated radiation sources were examined by comparing their dimensions(side length and thickness), weights and radioactivity of 40K. For comparison, radioactivity of 40K contained in 6 varieties of commercially available regular coffees was also measured. It was found that the dimensions and weights of the fabricated radiation sources did not significantly vary by difference of instant coffees, and the average radioactivity of 40K contained in the 10 coffee block radiation sources was 16.6Bq, being about 1.7times more intensive than that of regular coffees.
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Materials(Data)
Review Article
  • Katsumi HIROSE
    2015 Volume 64 Issue 12 Pages 753-764
    Published: December 15, 2015
    Released: December 29, 2015
    JOURNALS OPEN ACCESS
    Fukushima Dai-ichi Nuclear Power Plant(F1NPP) accident, which occurred as a result of huge earthquake and resulting tsunami, had a severe impact on world communities as did Japanese, because of cause of serious radioactivity contamination in the environment. Long-term effects of radioactivity contamination from F1NPP are concerned. To assess the long-term environmental effects of the F1NPP accident, it is important to review the history of global radioactivity contamination, which started from Hiroshima and Nagasaki nuclear explosions in Aug. 1945. Radionuclides released in the environment as a result of atmospheric nuclear explosions, nuclear reactor accident and others are migrated between atmosphere, hydrosphere, biosphere and lithosphere according to natural processes. We describe long-term environmental behaviors of anthropogenic radionuclides derived from the atmospheric nuclear explosions and others, which is useful to predict the behaviors and fate of the F1NPP-derived radionuclides.
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Serial Lectures
Neutron Scattering Study on Dynamics of Atomic and Molecular Motions
2-D Capturing of Radiations
  • Tatsuo TORII
    2015 Volume 64 Issue 12 Pages 775-782
    Published: December 15, 2015
    Released: December 29, 2015
    JOURNALS OPEN ACCESS
    Radioactive materials were diffused in the environment by the accident of the Fukushima Daiichi Nuclear Power Plant, TEPCO. Radiation monitoring from the sky is effective to find the contaminated areas quickly in Fukushima Prefecture, where 70% is occupied by the forests. In this report, it is given an outline about a monitoring technology from the sky using unmanned aerial vehicles and a new measuring technique under development as well as the aerial monitoring using the manned helicopter.
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