On residual 137Cs on shallow rugged reefs lying inshore of Fukushima: Part 2: Methodological improvements

Suzuki, Fumie; Imazeki, Masataka; Yamada, Jiro; Yamada, Yutaka; Kumagai, Noriyuki; Ohashi, Hideo; Shibata, Hiromi; Nogami, Ken-ichi; Shiotani, Nobuhiro

doi:10.51094/jxiv.600

##article.authors##

Suzuki, Fumie EcoStudies Association
Imazeki, Masataka Imazeki-Densou
Yamada, Jiro EcoStudies Association
Yamada, Yutaka EcoStudies Association
Kumagai, Noriyuki EcoStudies Association
Ohashi, Hideo EcoStudies Association
Shibata, Hiromi EcoStudies Association
Nogami, Ken-ichi EcoStudies Association
Shiotani, Nobuhiro EcoStudies Association

DOI:

https://doi.org/10.51094/jxiv.600

キーワード:

underwater CsI(Tl) gamma-ray spectrometer、 in situ and stationary measurement、 137Cs、 shallow rugged reefs

抄録

A newly improved underwater CsI(Tl) gamma-ray spectrometer was developed for in situ and stationary measurements of spectra of radiations on shallow rugged reefs lying inshore of Fukushima. Examination of the spectrometer using ⁴⁰K in a KCl test source and in slabs of granite justified the present method to confirm contact configuration between the detector and source. Furthermore, a spectrum of the Compton continuum due to coexisting ¹³⁷Cs and ¹³⁴Cs with the current ratio of ¹³⁴Cs/¹³⁷Cs was obtained to determine to a true energy spectrum of radiations on and near the interface between the contaminated surface of rock and seawater from a measured gamma-ray spectrum. The detector assembly was very useful in a situation where the depth was less than 30 m, the level of contamination was above 5×10³ Bq/m² of ¹³⁷Cs, and an allocated time of measurement at a point was about ten minutes.

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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 2

Methodological improvements