On residual 137Cs on shallow rugged reefs lying inshore of Fukushima: Part 1
Levels, distribution, and flux of radiations
DOI:
https://doi.org/10.51094/jxiv.599Keywords:
Fukushima Daiichi Nuclear Power Plant, Levels of 137Cs on rugged reefs, Simulation of transport of 662 keV gamma rays, Scalar flux of low energy gamma raysAbstract
Levels of residual 137Cs on reefs lying inshore of Fukushima were measured with the use of a newly improved underwater CsI(Tl) gamma-ray spectrometer. The levels varied from point to point, ranging from 1.0×104 Bq/m2 to 9.9×104 Bq/m2. All the measured spectra showed the presence of significant amounts of flux of gamma rays of energies less than 662 keV. With the use of an empirically determined spectrum of the Compton continuum inevitably created in the detector, a true spectrum of low energy gamma rays on and near the interface between contaminated rock surface and seawater was obtained. Analyses of transport of 662 keV gamma rays confirmed that those low energy gamma rays were derived from the multiple Compton scattering of 662 keV gamma rays emitted from residual 137Cs on the interface between the contaminated rock surface and seawater. A simple dose rate estimation is carried out for two ICRU tissue substitutes placed on the interface.
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Submitted: 2024-01-14 15:50:17 UTC
Published: 2024-01-20 00:52:44 UTC
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Copyright (c) 2024
Fumie Suzuki
Hideo Ohashi
Ken-ichi Nogami
Hiromi Shibata
Hisayuki Arakawa
Kentaro Umeda
Teiji Kobayasi
Nobuhiro Shiotani
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