A Knowledge-sharing activity on the environmental radiation monitoring results affected by the Fukushima-Daiichi Nuclear Power Plant Accident at Tokai-Oarai area in Ibaraki Prefecture

Nakano, Masanao; Hosomi, Kenji; Nishimura, Shusaku; Matsubara, Natsumi; Okura, Takehisa; Kuramochi, Akihiko; Kawasaki, Masatsugu; Takeuchi, Erina; Fujii, Yutaka*; Jinno, Tsukasa*; et al.

Hoken Butsuri (Internet), 55(2), p.102 - 109, 2020/06

https://doi.org/10.5453/jhps.55.102

After the Fukushima-Daiichi Nuclear Power Station (1F) Accident in March 2011, the increase was significantly observed in a part of the result of the environmental radiation monitoring in Ibaraki prefecture. "The review meeting of the environmental effect from 1F accident" was established to discuss technically the fluctuation of monitoring data. The review meeting collected the monitoring data from the four nuclear operators, and discussed a fluctuating trend, Cs/Cs activity ratio, and so on. In this report, the results of the dose rate and Cs in fallout, surface soil, flatfish and seabed sediment are introduced. Also the problem solving in the review meeting is introduced.

Detection of a gas region in a human body across a therapeutic carbon beam by measuring low-energy photons

Yamaguchi, Mitsutaka; Nagao, Yuto; Kawachi, Naoki; Sato, Takahiro; Fujimaki, Shu; Kamiya, Tomihiro; Torikai, Kota*; Shimada, Hirofumi*; Sugai, Hiroyuki*; Sakai, Makoto*; et al.

International Journal of PIXE, 26(1&2), p.61 - 72, 2016/00

https://doi.org/10.1142/S0129083516500078

no abstracts in English

Nonhomologous end-joining repair plays a more important role than homologous recombination repair in defining radiosensitivity after exposure to high-LET radiation

Takahashi, Akihisa*; Kubo, Makoto*; Ma, H.*; Nakagawa, Akiko*; Yoshida, Yukari*; Isono, Mayu*; Kanai, Tatsuaki*; Ono, Tatsuya*; Furusawa, Yoshiya*; Funayama, Tomoo; et al.

Radiation Research, 182(3), p.338 - 344, 2014/09

https://doi.org/10.1667/RR13782.1

To clarify whether high-LET radiation inhibits all repair pathways or specifically one repair pathway, studies were designed to examine the effects of radiation with different LET values on DNA DSB repair and radiosensitivity. Embryonic fibroblasts bearing repair gene KO were exposed to X rays, carbon-, iron-, neon- and argon-ion beams. Cell survival was measured with colony-forming assays. The sensitization enhancement ratio (SER) values were calculated using the 10% survival dose of wild-type cells and repair-deficient cells. Cellular radiosensitivity was listed in descending order: double-KO cells NHEJ-KO cells HR-KO cells wild-type cells. Although HR-KO cells had an almost constant SER value, NHEJ-KO cells showed a high-SER value when compared to HR-KO cells, even with increasing LET values. These results suggest that with carbon-ion therapy, targeting NHEJ repair yields higher radiosensitivity than targeting homologous recombination repair.

Frustration-induced magnetic properties of the spin-1/2 Heisenberg antiferromagnet on the Cairo pentagon lattice

Isoda, Makoto*; Nakano, Hiroki*; Sakai, Toru

Journal of the Physical Society of Japan, 83(8), p.084710_1 - 084710_7, 2014/08

https://doi.org/10.7566/JPSJ.83.084710

The spin-1/2 Heisenberg antiferromagnet on the Cairo pentagon lattice is investigated by the numerical diagonalization. As a result, it was found that an orthogonal dimer, the disorder, and the ferrimagnetic states appear depending on the ratio of the two exchange interactions.

Developing the soil moisture sensor using optical fiber technique (Joint research)

Komatsu, Mitsuru*; Nishigaki, Makoto*; Seno, Shoji*; Hirata, Yoichi*; Takenobu, Kazuyoshi*; Tagishi, Hirotaka*; Kunimaru, Takanori; Maekawa, Keisuke; Yamamoto, Yoichi; Toida, Masaru*; et al.

JAEA-Research 2012-001, 77 Pages, 2012/09

JAEA-Research-2012-001.pdf:4.85MB

This research focused on methods of estimating the amounts of groundwater recharge, which are normally required as upper boundary conditions in groundwater flow analyses, based on measurements of infiltrating water in the ground, to systematize the methods and establish systems which are stable and measurable on site over a long time. Regarding developing measurement systems, fiber-optic strain measurement methods that enable multiple-point and long-distance measurement were used for measuring three quantities: suction pressure, soil moisture and volumetric water content rate obtained by applying water absorption swelling material, and each measurement was discussed. The results showed that the fiber-optic soil aquameter has two types of practical application: one for measuring suction pressure (Type I), and the other for measuring volumetric water content rate obtained by applying water absorption swelling material (Type III). Furthermore, by using measurement instruments in actual fields, the validity of the two methods for estimating the rainfall infiltration capacities of shallow-layer soils, that is, estimating the capacities either directly by measurements of soil water or from unsaturated hydraulic conductivities, was confirmed.

XUV-FEL spectroscopy; He two-photon ionization cross-sections

Sato, Takahiro*; Iwasaki, Atsushi*; Ishibashi, Kazuki*; Okino, Tomoya*; Yamanouchi, Kaoru*; Adachi, Junichi*; Yagishita, Akira*; Yazawa, Hiroki*; Kannari, Fumihiko*; Aoyama, Makoto; et al.

Europhysics News, 42(5), P. 10, 2011/09

The resonant and non-resonant two-photon single ionization processes of He were investigated using intense free electron laser light in the extreme ultraviolet (XUV) region (53.4-61.4 nm) covering the 1s-2p and 1s-3p resonant transitions of He. On the basis of the dependences of the yield of He on the XUV light-field intensity at 53.4, 58.4, 56.0 and 61.4 nm, the absolute values of the two-photon ionization cross sections of He at the four different wavelengths and their dependence on the light-field intensity were determined for the first time.

Explanation of question and answer in special subject examination of the first test for professional engineer "nuclear and radiation" executed in 2010 fiscal year, Part 2; Nuclear section

Natsume, Tomohiro*; Nakano, Makoto*; Harada, Akio; Yamanaka, Atsushi; Kurihara, Ryoichi

Genshiryoku eye, 57(4), p.72 - 76, 2011/04

http://ci.nii.ac.jp/naid/40018753361

no abstracts in English

Commentaries for third secondary national examination on fiscal 2010 for the professional engineer of nuclear and radiation; Commentaries (Part 2) including key point for elective examinations

Sasaki, Satoru; Suzuki, Soju; Nakano, Junichi; Takamatsu, Misao; Matoba, Ichiyo*; Nakano, Makoto*; Oketani, Koichiro*; Natsume, Tomohiro*

Genshiryoku eye, 57(2), p.66 - 75, 2011/02

http://ci.nii.ac.jp/naid/40017428113

no abstracts in English

Degradation of charge collection efficiency for 6H-SiC diodes by electron irradiation

Iwamoto, Naoya; Onoda, Shinobu; Hishiki, Shigeomi; Oshima, Takeshi; Murakami, Makoto*; Nakano, Itsuo*; Kawano, Katsuyasu*

Materials Science Forum, 600-603(Part 2), p.1043 - 1046, 2009/00

The 6H-SiC np diodes were fabricated on a p-type substrate. To clarify the radiation resistance of the device performance, the diodes were irradiated with 1MeV-electrons at fluence up to 610/cm and the Charge Collection Efficiencies (CCEs) and diffusion length (L) of minority carriers were evaluated from the evaluation of the Transient Ion Beam Induced Current (TIBIC). The saturated CCE of 93% was obtained for non-electron irradiated diodes, and the value of CCE was kept up to electron fluences of 110/cm, although L decreased to 0.6m from 2.5m by the irradiation. The degradation of CCE was observed at fluences above 510/cm.

Analyses of benchmark problems for the shielding design of high intensity proton accelerator facilities

Matsuda, Norihiro; Iwamoto, Yosuke; Harada, Masahide; Teshigawara, Makoto; Meigo, Shinichiro; Maekawa, Fujio; Oguri, Tomomi*; Nakano, Hideo*; Nakao, Noriaki*; Nakane, Yoshihiro; et al.

JAEA-Technology 2008-030, 150 Pages, 2008/03

JAEA-Technology-2008-030.pdf:20.67MB

Radiation Shielding design/safety analysis required for licensing of the high intensity proton accelerator facility J-PARC (Japan Proton Accelerator Research Complex) is in progress, using various high-energy particle transport codes. Shielding benchmark problems, mainly based on experiments, on thick target neutron yield, beam dump geometry, deep penetration and radiation streaming were prepared and analyzed by the shielding design codes, in order to estimate the code's accuracy. The results of analyses show that the calculation results agree with the experiments within a factor of two on the whole.