著者

谷村 嘉彦 富田 純平 吉富 寛 吉澤 道夫 箱崎 亮三 高橋 荘平

出版者

日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.51, no.3, pp.141-146, 2016 (Released:2016-11-18)

参考文献数

10

被引用文献数

3

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Photon spectra were measured inside and outside a house in Minami-Soma city by using a NaI(Tl) scintillation spectrometer. The photons were categorized into three groups according to their energy. The groups were (1) scattered photons, which include low energy photons, (2) direct photons from 134Cs and 137Cs sources and (3) the other photons. Then the ratios of the ambient dose equivalents H*(10) of the scattered photons to those of the direct photons from the 134Cs and 137Cs sources have been evaluated from the measured photon spectra. The ratios are high inside the house compared with those out of the house. It was found that the scattered photons contribute to the H*(10) by more than 50% inside the house. The ambient dose equivalent average energies of the scattered photons are around 0.25 MeV both inside and outside the house. These data is worthwhile to design the optimum shielding for the protection against the public radiation exposure.

著者

谷村 嘉彦 平山 英夫 近藤 健次郎 永田 寛 岩永 宏平 鈴木 征四郎

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.15, no.3, pp.129-132, 2016 (Released:2016-08-15)

参考文献数

6

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Photon energy spectra were measured above the operating floor of unit 3 reactor at the Fukushima Daiichi Nuclear Power Station by using a CdZnTe semiconductor spectrometer. The spectrometer was installed in a lead collimator to measure the photons from the area directly below the detector. The collimator and spectrometer were lifted up by a huge crane and set above the operating floor. The photon spectra were derived by unfolding the pulse height spectra measured using the spectrometer. The response function of the spectrometer was calculated with the MCNP-4C code and was used as an input parameter of the unfolding code MAXED. It was found from the photon energy spectra that low-energy photons with energy below 0.4 MeV were dominant above the operating floor. These spectra are fundamental data for evaluating the dose reduction effect by setting up shields on the operating floor.