On residual 137Cs on shallow rugged reefs lying inshore of Fukushima: Part 1: Levels, distribution, and flux of radiations

Fumie Suzuki; Hideo Ohashi; Ken-ichi Nogami; Hiromi Shibata; Hisayuki Arakawa; Kentaro Umeda; Teiji Kobayasi; Nobuhiro Shiotani

doi:10.51094/jxiv.599

##article.authors##

Fumie Suzuki EcoStudies Association
Hideo Ohashi EcoStudies Association
Ken-ichi Nogami EcoStudies Association
Hiromi Shibata EcoStudies Association
Hisayuki Arakawa Faculty of Marine Resouces and Environment, Tokyo University of Marine Science and Technology
Kentaro Umeda Department of Electric and Electronic Engineering, Tohoku Institute of Technology
Teiji Kobayasi Tohoku University
Nobuhiro Shiotani EcoStudies Association

DOI:

https://doi.org/10.51094/jxiv.599

キーワード:

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 rays

抄録

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.

利益相反に関する開示

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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On residual 137Cs on shallow rugged reefs lying inshore of Fukushima: Part 1

Levels, distribution, and flux of radiations