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Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Namba, Kenji*; Neda, Hitoshi*; Sasaki, Yoshito; Niizato, Tadafumi; Watanabe, Naoko*; Kozaki, Tamotsu*
Environmental Science; Processes & Impacts, 21(7), p.1164 - 1173, 2019/07
Times Cited Count：10 Percentile：43.97(Chemistry, Analytical)The fate of radioactive Cs deposited after the Fukushima nuclear power plant accident and its associated radiological impacts are largely dependent on its mobility from surface soils to forest ecosystems. We measured the accumulation of radioactive Cs in the fruit bodies of wild fungi in the forest at Iidate, Fukushima, Japan. The transfer factors (TFs) of radioactive Cs from soil to the fruit bodies of wild fungi were between 10 
to 10
, a range similar to those reported for the fruit bodies collected in Europe after the Chernobyl accident and in parts of Japan contaminated by nuclear bomb test fallout. Comparison of the TFs of the wild mushroom and that of the fungal hyphae of 704 stock strains grown on agar medium containing nutrients and radioactive Cs showed that the TFs of wild mushroom were lower. TF was less than 0.1 after addition of the minerals zeolite, vermiculite, phlogopite, smectite, or illite of 1% weight to the agar medium. These results indicate that the presence of minerals decrease Cs uptake by fungi grown in the agar medium.
Nishiuchi, Mamiko*; Sakaki, Hironao*; Esirkepov, T. Zh.*; Nishio, Katsuhisa; Pikuz, T. A.*; Faenov, A. Ya.*; Skobelev, I. Yu.*; Orlandi, R.; Pirozhkov, A. S.*; Sagisaka, Akito*; et al.
Plasma Physics Reports, 42(4), p.327 - 337, 2016/04
Times Cited Count：13 Percentile：59.02(Physics, Fluids & Plasmas)A combination of a petawatt laser and nuclear physics techniques can crucially facilitate the measurement of exotic nuclei properties. With numerical simulations and laser-driven experiments we show prospects for the Laser-driven Exotic Nuclei extraction-acceleration method proposed in [M. Nishiuchi et al., Phys. Plasmas 22, 033107 (2015)]: a femtosecond petawatt laser, irradiating a target bombarded by an external ion beam, extracts from the target and accelerates to few GeV highly charged short-lived heavy exotic nuclei created in the target via nuclear reactions.
Onuki, Toshihiko; Sakamoto, Fuminori; Yamasaki, Shinya*; Kozai, Naofumi; Shiotsu, Hiroyuki; Utsunomiya, Satoshi*; Watanabe, Naoko*; Kozaki, Tamotsu*
Journal of Environmental Radioactivity, 144, p.127 - 133, 2015/06
Times Cited Count：9 Percentile：26.87(Environmental Sciences)The accumulation of Cs by unicellular fungus of in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica 
smectite, illite 
vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals.
Nishiuchi, Mamiko; Sakaki, Hironao; Esirkepov, T. Z.; Nishio, Katsuhisa; Pikuz, T. A.*; Faenov, A. Ya.*; Pirozhkov, A. S.; Sagisaka, Akito; Ogura, Koichi; Kanasaki, Masato; et al.
Research Using Extreme Light; Entering New Frontiers with Petawatt-Class Lasers II (Proceedings of SPIE, Vol.9515), p.95151D_1 - 95151D_4, 2015/06
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)Experimental demonstration of multi-charged heavy ion acceleration from the interaction between the ultra-intense short pulse laser system and the metal target is presented. The laser pulse of 
10 J laser energy, 36 fs pulse width, and the contrast level of 
10
from 200 TW class Ti:sapphire J-KAREN laser system at JAEA is used in the experiment. Almost fully stripped Fe ions accelerated up to 0.9 GeV are demonstrated. This is achieved by the high intensity laser field of 10
Wcm interacting with the solid density target. The demonstrated iron ions with high charge to mass ratio (Q/M) is difficult to be achieved by the conventional heavy ion source technique in the accelerators.
Zn
(T: Rh and Ir)Honda, Fuminori*; Hirose, Yusuke*; Miyake, Atsushi*; Mizumaki, Masaichiro*; Kawamura, Naomi*; Tsutsui, Satoshi*; Watanuki, Tetsu; Watanabe, Shinji*; Takeuchi, Tetsuya*; Settai, Rikio*; et al.
Journal of Physics; Conference Series, 592(1), p.012021_1 - 012021_5, 2015/03
Times Cited Count：3 Percentile：72.07(Physics, Atomic, Molecular & Chemical)no abstracts in English
Nishiuchi, Mamiko; Sakaki, Hironao; Esirkepov, T. Z.; Nishio, Katsuhisa; Pikuz, T.*; Faenov, A.*; Skobelev, I. Yu.*; Orlandi, R.; Sako, Hiroyuki; Pirozhkov, A. S.; et al.
Physics of Plasmas, 22(3), p.033107_1 - 033107_8, 2015/03
Times Cited Count：72 Percentile：96.78(Physics, Fluids & Plasmas)Almost fully stripped Fe ions accelerated up to 0.9 GeV are demonstrated with a 200 TW femtosecond high-intensity laser irradiating a micron-thick Al foil with Fe impurity on the surface. An energetic low-emittance high-density beam of heavy ions with a large charge-to-mass ratio can be obtained, which is useful for many applications, such as a compact radio isotope source in combination with conventional technology.
Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A.*; Ogura, Koichi; Fukami, Tomoyo; Matsukawa, Kenya*; et al.
Review of Scientific Instruments, 85(2), p.02A705_1 - 02A705_4, 2014/02
Times Cited Count：2 Percentile：11.15(Instruments & Instrumentation)High intensity laser-plasma interaction has attracted considerable interest for a number of years. The laser-plasma interaction is accompanied by generation of various charged particle beams. Results of simultaneous novel measurements of electron-induced photonuclear neutrons (photoneutron), which are a diagnostic of the laser-plasma interaction, are proposed to use for optimization of the laser-plasma ion generation. The proposed method is demonstrated by the laser irradiation with the intensity os 1
10 W/cm on the metal foil target. The photoneutrons are measured by using NE213 liquid scintillation detectors. Heavy-ion signal is registered with the CR39 track detector simultaneously. The measured signals of the electron-induced photoneutrons are well reproduced by using the Particle and Heavy Ion Transport code System (PHITS). The results obtained provide useful approach for analyzing the various laser based ion beams.
Kozai, Naofumi; Onuki, Toshihiko; Arisaka, Makoto; Watanabe, Masayuki; Sakamoto, Fuminori; Yamasaki, Shinya; Jiang, M.
Journal of Nuclear Science and Technology, 49(5), p.473 - 478, 2012/05
Times Cited Count：65 Percentile：97.78(Nuclear Science & Technology)Chemical states of radioactive Cs in the contaminated soils by Fukushima Daiichi Nuclear Power Plant accident has been characterized by the desorption experiments using appropriate reagents solutions and size fractionation of the contaminated soils. Approximately 70% of radioactive Cs in the residual fraction were associated with the size fractions larger than the elutriated one, even though mica-like minerals were contained in the elutriated one. These results strongly suggest that radioactive Cs was irreversibly associated with soil components other than mica like minerals in the contaminated soil.
Kumamoto, Yuichiro*; Aramaki, Takafumi*; Watanabe, Shuichi*; Yoneda, Minoru*; Shibata, Yasuyuki*; Togawa, Orihiko; Morita, Masatoshi*; Shitashima, Kiminori*
Journal of Oceanography, 64(3), p.429 - 441, 2008/06
Times Cited Count：11 Percentile：25.29(Oceanography)In 1995 and 2000, radiocarbon ratio (
C) of total dissolved inorganic carbon was measured in the Japan Sea, a semi-closed marginal sea in the western North Pacific, where deep and bottom waters are formed in itself. Compiling them with historical radiocarbon data in the Japan Sea, temporal and spatial variations of the radiocarbon in the bottom water below 2000 m depth were elucidated. C in the bottom waters in the western Japan and Yamato Basins increased by about 20 ‰ between 1977/79 and 1995 and did not changed between 1995 and 1999/2000, suggesting penetration of surface bomb-produced radiocarbon into the bottom waters due to bottom ventilation in the earlier period and stagnation of the bottom ventilation in the following period, respectively. In the eastern Japan Basin, the bottom C increased by about 10 ‰ between 1977/79 and 2002, suggesting less ventilation of the bottom water in the basin. The temporal changes of the radiocarbon, tritium, and dissolved oxygen suggest sporadic occurrences of the bottom ventilation between 1979 and 1984 and its stagnation between 1984 and 2004 in the eastern Japan and Yamato Basins. The former is probably due to spreading of a newly ventilated bottom water in the western Japan Basin in the severe winter of 1976-1977 along the abyssal circulation in the Japan Sea. The latter does not conflict with temporal changes of bomb-produced 
Cs and chlorofluorocarbon-11 in the bottom water.
Ikeda, Yoshitaka; Akino, Noboru; Ebisawa, Noboru; Hanada, Masaya; Inoue, Takashi; Honda, Atsushi; Kamada, Masaki; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; et al.
Fusion Engineering and Design, 82(5-14), p.791 - 797, 2007/10
Times Cited Count：22 Percentile：80.6(Nuclear Science & Technology)Modification of JT-60U to a superconducting device (so called JT-60SA) has been planned to contribute to ITER and DEMO. The NBI system is required to inject 34 MW for 100 s. The upgraded NBI system consists of twelve positive ion based NBI (P-NBI) units and one negative ion based NBI (N-NBI) unit. The injection power of the P-NBI units are 2 MW each at 85 keV, and the N-NBI unit will be 10 MW at 500 keV, respectively. On JT-60U, the long pulse operation of 30 s at 2 MW (85 keV) and 20 s at 3.2 MW (320 keV) have been achieved on P-NBI and N-NBI units, respectively. Since the temperature increase of the cooling water in both ion sources is saturated within 20 s, further pulse extension up to 100 s is expected to mainly modify the power supply systems in addition to modification of the N-NBI ion source for high acceleration voltage. The detailed technical design of the NBI system for JT-60SA is presented.
Sekine, Toshiaki; Izumo, Mishiroku; Matsuoka, Hiromitsu; Kobayashi, Katsutoshi; ; Osa, Akihiko; Koizumi, Mitsuo; Motoishi, Shoji; Hashimoto, Kazuyuki; ; et al.
Proc. of the 5th Int. Workshop on Targetry and Target Chemistry, 0, p.347 - 352, 1994/00
no abstracts in English
Ikeda, Yoshitaka; Okano, Fuminori; Hanada, Masaya; Sakasai, Akira; Miya, Naoyuki; Watanabe, Takashi*; Daigo, Yasuhiko*; Hosogane, Nobuyuki*; Aoto, Mitsuo*
no journal, ,
JT-60, to which the Radiation Hazard Prevention Act is applied, stopped its operation in October 2008 after 18 years deuterium operation since 1991. JT-60 will be upgraded to JT-60SA with superconducting magnet coils, which is the Satellite Tokamak Program under the EU-Japan collaboration, so as to demonstrate the high-beta long-pulse plasma operation. To establish this new device, the existing JT-60 facilities such as magnetic coils, vacuum vessel, basement, diagnostics and heating system. The disassembly of JT-60 is featured by the radiactivation of all components due to neutron from the D-D reaction, and thus, one of the main issues is to manage the physical control of the radiated material for the application of clearance regulation. The disassembly has started since 2009 and will complete by the autumn of 2012. Then a new JT-60SA basement, which will be shipped from EU, will be installed within March 2013.
Onuki, Toshihiko; Kozai, Naofumi; Arisaka, Makoto; Watanabe, Masayuki; Sakamoto, Fuminori
no journal, ,
Chemical states of radioactive Cs in the contaminated soils by Fukushima Daiichi Nuclear Power Plant accident has been characterized by the desorption experiments using appropriate reagents solutions and size fractionation of the contaminated soils. The results strongly suggest that radioactive Cs was irreversibly associated with soil components other than mica like minerals in the contaminated soil.
Sakaki, Hironao; Fukuda, Yuji; Kanasaki, Masato; Nishiuchi, Mamiko; Jinno, Satoshi; Yogo, Akifumi; Fukami, Tomoyo; Kondo, Kiminori; Sato, Tatsuhiko; Watanabe, Yukinobu; et al.
no journal, ,
Generally, if several-tens MeV electron is dumped into some material, photons with the same energy level are created by bremsstrahlung radiation. And then neutron is generated because of the (g, n) reactions. In current researches, electron energies are getting higher as the high-energy ions are generated. Therefore, when the energy of laser driven accelerated ion exceeds several-tens of MeV, it is impossible to disregard the neutron generation from the (g, n) reactions. Although such a neutron becomes as a background-nose of the ion measurement, a quantitative evaluation has not carried out in the laser-driven ions acceleration experiments yet. We report an evaluation of those neutron properties by using measurement data in the laser-plasma interaction experiments, and it is discussed with a result of Monte Carlo simulation including the (g, n) reaction processes.
Okano, Fuminori; Ikeda, Yoshitaka; Sakasai, Akira; Hanada, Masaya; Watanabe, Takashi*; Daigo, Yasuhiko*; Hosogane, Nobuyuki*; Aoto, Mitsuo*
no journal, ,
no abstracts in English
Ikeda, Yoshitaka; Okano, Fuminori; Hanada, Masaya; Sakasai, Akira; JT-60 Team; Watanabe, Takashi*; Daigo, Yasuhiko*; Hosogane, Nobuyuki*; Aoto, Mitsuo*
no journal, ,
Break-even Plasma Test Facilities (JT-60) is the only tokamak device applied by the Radiation Hazard Prevention Act, and is under upgrading towards the super-conducting magnetic device "JT-60SA" aiming long pulse and high beta plasmas. The JT-60SA project is in progress as the satellite Tokamak project under the Japan-EU international program "ITER Broader Approach". At the first step towards JT-60SA, the disassembly of JT-60 tokamak and its affiliated facilities was done for three years and completed in October 2012. All disassembly and cutting works were in control of radiation management. Total number and weight of disassembly components were about 13000 and about 5400 tons, respectively. The JT-60 was composed of a lot of high mechanical strength materials such as high manganese steel which is difficult-to-machine material. New technologies such as a diamond wire-saw which cut the complicated structure simultaneously enabled the effective disassembly.
Sagisaka, Akito; Nishiuchi, Mamiko; Pirozhkov, A. S.; Ogura, Koichi; Sakaki, Hironao; Maeda, Shota; Pikuz, T.; Faenov, A. Ya.*; Fukuda, Yuji; Yogo, Akifumi; et al.
no journal, ,
High-intensity laser and thin-foil interactions produce high-energy particles, hard X-ray, high-order harmonics, and terahertz radiation. A proton beam driven by a high-intensity laser has received attention as a compact ion source for medical and other applications. We have performed several high intensity laser-matter interaction experiments using a thin-foil target irradiated by Ti:sapphire laser (J-KAREN) at JAEA. The pulse duration was typically 40 fs (FWHM). The electron density profiles of the preformed plasma were observed with the interferometer. The high temporal contrast laser system could reduce the preformed plasma. The maximum proton energy gradually increased as the laser performance improved and finally protons of 40 MeV energy were observed at the peak laser intensity of 1 10 W/cm.
Nishiuchi, Mamiko; Sakaki, Hironao; Sagisaka, Akito; Maeda, Shota; Pirozhkov, A. S.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.
no journal, ,
no abstracts in English
Maeda, Shota; Nishiuchi, Mamiko; Sakaki, Hironao; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.
no journal, ,
In JAEA, the high energy ions generated by the interaction between Ultra-intense Ultra-Short pulse laser and thin-foil target is being studied. Irradiating condition must be optimized to generate higher energy ions while suppress the becoming gigantic of laser. It is necessary to know the physical phenomenon in plasma to determine the parameter to optimize from the information on the electron and neutron, X-rays, which are generated simultaneously with ion. In this study, in order to measure electron temperature accurately, an electron spectrometer was developed which have broad range (1-200 MeV). The detector is comprised of permanent magnets and a fluorescent plate, CCD camera. In the presentation, the result of the calibration experiment carried out using 4, 9, 12, 15 MeV quasi-monoenergetic electron beam in HIBMC will be reported. Moreover, response analysis method was inspected using PHITS which is particle transporting Monte Carlo simulation code, and will also report the result.
Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A. Y.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.
no journal, ,
We report that the results of simultaneous novel measurements of electron-induced photonuclear neutrons (photoneutron), which are a diagnostic of the laser-plasma interaction. The proposed method is demonstrated by the laser irradiation with the intensity of 110 W/cm on the metal foil target. The photoneutrons are measured by using NE213 liquid scintillation detectors. The measured signals of the electron-induced photoneutrons are well reproduced by using the Particle and Heavy Ion Transport code System (PHITS).
