Japanese Journal of Health Physics

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Plastic scintillator (PS) sheets were treated with dielectric barrier discharge plasma (DBD) or by fluorine gas (F-gas) to become its surface hydrophilicity. A hydrophobic PS-sheet changed by these treatments and contact area of sample solution became wide, so measurement efficiency of beta-rays became higher than before treatment. Surface treatment was effective, especially for low energy beta-rays. Average measurement efficiency was approx. 35% for 5 μL tritium samples with 1 min. plasma treatment, and count rate showed good linearity with activity (Bq) from 2 to 400 Bq/5 μL. Little radioactive waste was generated by the PS-sheets method because the PS-sheets were measured by a conventional liquid scintillation counter (LSC) without liquid scintillator and they were possible to reuse by simple rinsing. Also unquenching spectra was gotten by the PS-sheets. The PS-sheets method is possible both of qualitative and quantitative analysis without radioactive wastes.

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While the revised dose limit for the lens of the eye was presented by the International Commission on Radiological Protection (ICRP), the dose measurement standards for the lens of the eye have been discussed in the International Organization for Standardization (ISO). In the International Basic Safety Standards of International Atomic Energy Agency (IAEA), a new ICRP dose limit of the lens of the eye was included, and a technical document was published as a guidance on the implications of the new dose limit for the lens of the eye for occupational radiation protection. By the International Radiation Protection Association (IRPA) Task Group on Implementation of Revised Dose Limits to the Lens of the Eye, the opinions for the new ICRP dose limit for the lens of the eye are investigated for the member states. In this paper, the progress of discussion in these organizations is reported.

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A carborne survey system named as KURAMA (Kyoto University RAdiation MApping system) has been developed as a response to the nuclear accident at TEPCO Fukushima Daiichi Nuclear Power Plant in 2011. Now the system evolved into a CompactRIO-based KURAMA-II, and serves for the various types of applications. More than a hundred of KURAMA-II are deployed for the periodical drawing of the radiation map in the East Japan by Japanese government. A continuous radiation monitoring by KURAMA-II on local buses is started in Fukushima prefecture as the collaboration project among Kyoto University, Fukushima prefectural government, and JAEA. Extended applications such as precise radiation mappings in farmlands and parks are also on the way. The developments, present status and future prospects of KURAMA and KURAMA-II are introduced.

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