著者

Hidehito NAKAMURA Yoshiyuki SHIRAKAWA Hisashi KITAMURA Nobuhiro SATO Sentaro TAKAHASHI

出版者

一般社団法人日本保健物理学会

雑誌

保健物理 (ISSN:03676110)

巻号頁・発行日

vol.49, no.2, pp.98-101, 2014 (Released:2015-05-21)

参考文献数

25

被引用文献数

7 9

---

The enormous area of damage to Japan's Fukushima Daiichi nuclear power plant requires radiation detectors with robust base substrates to monitor high-dose-rate environmental radiation with long-term stability. Undoped aromatic ring polymers have considerable potential as base substrates in radiation detection. Here, we characterise polycarbonate (PC), which has excellent transparency, shock, radiation, and weather resistance, heat tolerance, and anti-abrasion qualities. It has a density of 1.20 g/cm3, an excitation maximum of 310 nm, and short-wavelength emission with a maximum at 350-nm. By taking into account its emission spectrum, we determined an effective refractive index of 1.64. PC has a light yield that is 0.67 times that of undoped poly (ethylene terephthalate). These results reveal that readily available PC is an effective base substrate for use in large-area radiation detectors for the nuclear power plant recovery process.

著者

Masao SUZUKI Chizuru TSURUOKA Yukio UCHIHORI Hisashi KITAMURA Cui Hua LIU

出版者

Journal of Radiation Research Editorial Committee

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.50, no.5, pp.395-399, 2009 (Released:2009-09-16)

参考文献数

23

被引用文献数

2

---

We studied cellular responses in normal human fibroblasts induced with low-dose (rate) or low-fluence irradiations of different radiation types, such as gamma rays, neutrons and high linear energy transfer (LET) heavy ions. The cells were pretreated with low-dose (rate) or low-fluence irradiations (~1 mGy/7-8 h) of 137Cs gamma rays, 241Am-Be neutrons, helium, carbon and iron ions before irradiations with an X-ray challenging dose (1.5 Gy). Helium (LET = 2.3 keV/μm), carbon (LET = 13.3 keV/μm) and iron (LET = 200 keV/μm) ions were produced by the Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. No difference in cell-killing effect, measured by a colony forming assay, was observed among the pretreatment with different radiation types. In mutation induction, which was detected in the hypoxanthine-guanine phosphoribosyltransferase (hprt) locus to measure 6-thioguanine resistant clones, there was no difference in mutation frequency induced by the X-ray challenging dose between unpretreated and gamma-ray pretreated cells. In the case of the pretreatment of heavy ions, X-ray-induced mutation was around 1.8 times higher in helium-ion pretreated and 4.0 times higher in carbon-ion pretreated cells than in unpretreated cells (X-ray challenging dose alone). However, the mutation frequency in cells pretreated with iron ions was the same level as either unpretreated or gamma-ray pretreated cells. In contrast, it was reduced at 0.15 times in cells pretreated with neutrons when compared to unpretreated cells. The results show that cellular responses caused by the influence of hprt mutation induced in cells pretreated with low-dose-rate or low-fluence irradiations of different radiation types were radiation-quality dependent manner.Translated and modified from Radiat. Biol. Res. Comm. Vol.43(4); 424-435, (2008, in Japanese).