Direct energy conversion using Ni/SiC Schottky junction in Np and Am gamma ray regions

Fukuda, Tatsuo; Kobata, Masaaki; Shobu, Takahisa; Yoshii, Kenji; Kamiya, Junichiro; Iwamoto, Yosuke; Makino, Takahiro*; Yamazaki, Yuichi*; Oshima, Takeshi*; Shirai, Yasuhiro*; et al.

Journal of Applied Physics, 132(24), p.245102_1 - 245102_8, 2022/12

https://doi.org/10.1063/5.0099136

Direct energy conversion has been investigated using Ni/SiC Schottky junctions with the irradiation of monochromatized synchrotron X-rays simulating the gamma rays of Np (30 keV) and Am (60 keV). From current-voltage measurements, electrical energies were obtained for both kinds of gamma rays. The energy conversion efficiencies were found to reach up to 1.6%, which is comparable to those of a few other semiconducting systems reported thus far. This result shows a possibility of energy recovery from nuclear wastes using the present system, judging from the radiation tolerant nature of SiC. Also, we found different conversion efficiencies between the two samples. This could be understandable from hard X-ray photoelectron spectroscopy and secondary ion mass spectroscopy measurements, suggesting the formation of Ni-Si compounds at the interface in the sample with a poor performance. Hence, such combined measurements are useful to provide information that cannot be obtained by electrical measurements alone.

Feasibility study of the one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

Journal of Nuclear Engineering and Radiation Science, 7(4), p.042002_1 - 042002_7, 2021/10

https://doi.org/10.1115/1.4048841

For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station (FDNPS) buildings, we propose a novel one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding. The proposed method estimates the incident position of radiation to the fiber by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of light along the fiber depends on the wavelength. Because this method measures the integrated light intensity, this method can avoid the problem of counting loss and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field. Through basic experiments using the ultraviolet light source and Sr/Y radioactive point source, basic properties of source position detection were confirmed.

Factors controlling Cs activity concentrations in sediment collected off the coast of Fukushima Prefecture in 2013-2015

Fukuda, Miho*; Aono, Tatsuo*; Yamazaki, Shinnosuke*; Ishimaru, Takashi*; Kanda, Jota*; Nishikawa, Jun*; Otosaka, Shigeyoshi

Geochemical Journal, 52(2), p.201 - 209, 2018/00

https://doi.org/10.2343/geochemj.2.0504

To elucidate recent activity levels and the behavior of radiocesium in the coast off Fukushima Prefecture, lateral and vertical distributions of Cs in sediment were observed in 2013-2015 at 12 monitoring stations. At stations around the water depth of 100 m, relatively higher Cs activities were observed from surface sedimentary layer (0-3 cm). In these stations, sediments had high content of silt to clay particles and organic matter. The high Cs activities in the surface sediments were attributed to accumulation of highly mobile sediment particles. In October 2014, at some coastal stations, sharp peaks of Cs activities were observed in the subsurface (5-16 cm) sediments, whereas such broad peaks were not found in October 2015. These results suggest that the Cs activities in sediment had largely changed by lateral transport and re-sedimentation on the surface, as well as sediment mixing in the middle-layers.

Lethal and mutagenic effects of ion beams and -rays in

Toyoshima, Yoshiyuki*; Takahashi, Akemi*; Tanaka, Hisaki*; Watanabe, Jun*; Mogi, Yoshinobu*; Yamazaki, Tatsuo*; Hamada, Ryoko*; Iwashita, Kazuhiro*; Sato, Katsuya; Narumi, Issei

Mutation Research; Fundamental and Molecular Mechanisms of Mutagenesis, 740(1-2), p.43 - 49, 2012/12

https://doi.org/10.1016/j.mrfmmm.2012.12.005

Unconventional ferroelectric transition in the multiferroic compound TbMnO revealed by the absence of an anomaly in -polarized phonon dispersion

Kajimoto, Ryoichi; Sagayama, Hajime*; Sasai, Kenzo*; Fukuda, Tatsuo; Tsutsui, Satoshi*; Arima, Takahisa*; Hirota, Kazuma*; Mitsui, Yukari*; Yoshizawa, Hideki*; Baron, A. Q. R.*; et al.

Physical Review Letters, 102(24), p.247602_1 - 247602_4, 2009/06

https://doi.org/10.1103/PhysRevLett.102.247602

Mutation bleeding of soy sauce brewing microorganisms using ion beams

Toyoshima, Yoshiyuki*; Tanaka, Hisaki*; Akagawa, Takumi*; Yamazaki, Tatsuo*; Sato, Katsuya; Hase, Yoshihiro; Narumi, Issei

Hoshasen To Sangyo, (119), p.22 - 26, 2008/09

http://ci.nii.ac.jp/naid/40016236707

no abstracts in English

Preliminary results of surface-based investigation at the Horonobe url site, Japan

Yamazaki, Shinichi; Fukushima, Tatsuo; Aoki, Kazuhiro

Proceedings of 2nd International Meeting on Clays in Natural and Engineered Barriers for Radioactive Waste Confinement, p.59 - 60, 2005/03

Two off-site Underground Research Laboratory (URL) projects, which are mentioned in the

International Workshop on Horonobe Underground Research Laboratory Project abstracts

Yamazaki, Shinichi; Matsui, Hiroya; Hama, Katsuhiro; Morioka, Hiroshi; Hatanaka, Koichiro; Fukushima, Tatsuo

JNC TN5400 2004-004, 41 Pages, 2004/10

JNC-TN5400-2004-004.pdf:4.66MB

Japan Nuclear Cycle Development Institute (JNC) is pursuing two underground research laboratory (URL) projects to conduct a systematic research on geological disposal of high level radioactive wastes. The Tono Geoscience Center (TGC) has been carrying out research and development in crystalline rocks at Mizunami in central Japan and the Horonobe Underground Research Center in sedimentary rocks at Horonobe in northern Japan. Both projects are nearing termination of the first phase of surface-based investigation and is about to move on to the next phase of actually constructing the facilities underground. To mark this transition of phases, an international conference is organized to promote domestic and international recognition for the significance of constructing the URLs by disseminating research findings to a broad range of researchers and specialists from within and outside Japan as well as to the local community.

Removal of hydrogen from co-deposits on JT-60 open divertor using pulse laser ablation; Laser wavelength dependence

Sakawa, Yoichi*; Watanabe, Daisuke*; Shoji, Tatsuo*; Yamazaki, Kozo*; Masaki, Kei; Tanabe, Tetsuo*

no journal, , 

no abstracts in English

Development of breeding method for using ion beams

Toyoshima, Yoshiyuki*; Akagawa, Takumi*; Yamazaki, Tatsuo*; Ura, Tetsuji*; Sato, Katsuya; Hase, Yoshihiro; Narumi, Issei

no journal, , 

no abstracts in English