On residual 137Cs on shallow rugged reefs lying inshore of Fukushima: Part 2
Methodological improvements
DOI:
https://doi.org/10.51094/jxiv.600Keywords:
underwater CsI(Tl) gamma-ray spectrometer, in situ and stationary measurement, 137Cs, shallow rugged reefsAbstract
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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Submitted: 2024-01-14 16:48:15 UTC
Published: 2024-01-20 00:55:39 UTC
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Copyright (c) 2024
Fumie Suzuki
Masataka Imazeki
Jiro Yamada
Yutaka Yamada
Noriyuki Kumagai
Hideo Ohashi
Hiromi Shibata
Ken-ichi Nogami
Nobuhiro Shiotani
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