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Auh, Y. H.*; Neal, N. N.*; Arole, K.*; Regis, N. A.*; Nguyen, T.*; Ogawa, Shuichi*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Radovic, M.*; Green, M. J.*; et al.
ACS Applied Materials & Interfaces, 17(21), p.31392 - 31402, 2025/05
Times Cited Count：4 Percentile：77.77(Nanoscience & Nanotechnology)Collaborative Laboratories for Advanced Decommissioning Science; Kyoto University*
JAEA-Review 2019-036, 65 Pages, 2020/03
JAEA-Review-2019-036.pdf:4.46MB
JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Quantitative Analysis Method for Radiation Distribution in High Radiation Environment by Gamma-ray Image Spectroscopy". Electron-tracking Compton camera (ETCC) has been developed originally for nuclear gamma-ray astronomy, and also applied to medical use as a technology that greatly improves the resolution of conventional Compton camera by measuring three-dimensional tracking of electrons using a gaseous 3-dimensional position detector (so called Time Projection Chamber) in the first stage. In the present study, based on the ETCC that has been developed for medical use, we produce a prototype of light weight ETCC with the emphasis on the operability at the site, and evaluate its practicability by field tests.
Sako, Hiroyuki; Sugimura, Hitoshi; Ahn, J. K.*; Han, Y.*; Hasegawa, Shoichi; Hwang, S. H.*; Ichikawa, Yudai; Imai, Kenichi; Kiuchi, Ryuta*; Ozawa, Kyoichiro; et al.
Nuclear Instruments and Methods in Physics Research A, 763, p.65 - 81, 2014/11
Times Cited Count：5 Percentile：35.48(Instruments & Instrumentation)We developed a prototype TPC for an H-dibaryon search experiment at J-PARC. To investigate its performance, we conducted tests with Ar-CH
(90:10) and Ar-CF (95:5), where the former is mainly used. The detection efficiency was measured to be 98% at the beam rate up to 
cps/cm
, and 90% at the rate of 
cps/cm. Based on the measured horizontal resolution of 0.19-0.46 mm at the drift length of 5-20 cm, the position resolution of better than 0.3 mm is estimated in 1 T magnetic field. The ion backflow fraction was measured to be 5% and reduced up to 3% at the gain of 
. The horizontal position distortion due to ion backflow in the gate operation was suppressed within 
mm at the beam rates up to cps/cm. On the other hand, the distortion with the gate open was measured to be 
mm. The distortion in the final experiment is estimated to be 
mm.
No and its 
-decay daughter 
FmAsai, Masato; Tsukada, Kazuaki; Sakama, Minoru*; Ichikawa, Shinichi; Ishii, Tetsuro; Nagame, Yuichiro; Nishinaka, Ichiro; Akiyama, Kazuhiko; Osa, Akihiko; Oura, Yasuji*; et al.
Physical Review Letters, 95(10), p.102502_1 - 102502_4, 2005/09
Times Cited Count：67 Percentile：87.64(Physics, Multidisciplinary)Excited states in Fm fed by the decay of No have been established through -
and -electron coincidence spectroscopy using a gas-jet transport system and an on-line isotope separator. The spin-parity of the 124.1 keV level in Fm has been identified on the basis of the measured internal conversion coefficients. The ![$$nu 3/2^{+}[622]$$](/search/images/EROG23JAGMXTEXT1FN4VWNRSGJOSI.gif)
configuration has been assigned to the ground state of No as well as to the 124.1 keV level. It was found that the ground state configuration of No is different from that of lighter 
isotones.
Bakhtiari, M.; Tamai, Hiroshi; Kawano, Yasunori; Kramer, G. J.*; Isayama, Akihiko; Nakano, Tomohide; Kamiya, Kensaku; Yoshino, Ryuji; Miura, Yukitoshi; Kusama, Yoshinori; et al.
Nuclear Fusion, 45(5), p.318 - 325, 2005/05
Times Cited Count：50 Percentile：80.06(Physics, Fluids & Plasmas)In the previous works we had shown that injecting a mixture of large amounts of hydrogen and small amounts of argon can terminate a tokamak discharge quickly with avoiding runaway electron generation. In this work we have done the same experiments but with different gases in addition to argon. In fact we compared the effect of the puffing of argon, krypton, and xenon gases with and without simultaneous hydrogen gas puffing on disruption mitigation. We observed that injecting all impurities in the form of an admixture in hydrogen lead to faster plasma shutdowns with less runaway electron generation. We also found that injecting krypton gas (with or without hydrogen) seems to be a good candidate for plasma shutdown purposes since it induces low heat flux to divertor plates and avoids runaway electron generation more effectively.
Kojima, Takuji
Shinku, 47(11), p.789 - 795, 2004/11
When flue gas/off gas is irradiated by EB, many free radicals such as OH and active oxygen atom are formed from major components of air: namely nitrogen, oxygen, water and carbon dioxide ecules. The similer reaction can be achieved using UV light and plasma-discharging, but ionizing radiations produce such free radicals at higher density. Such radiation-induced radicals react efficiently with air pollutants, SOx and NOx in coal/oil combustion flue gas at thermal power plants, dioxins in waste incineration flue gas and volatile organic compounds (VOC) even in very low concentration and decompose them into non-toxic substances or change them to removable substances. R & D on EB treatment of flue gas/off gas done in JAERI on the basis of this principle process, as an example, is described in the present paper.
Kojima, Takuji
Shokubai, 46(3), p.248 - 253, 2004/04
The present paper describes research and development on purification technology using electron beams for flue/odd gases containing pollutants: removal of sulfate oxide and nitrogen oxide from flue gases of coal/oil combustion power plants, decomposition of dioxins in waste incineration flue gas, and decomposition/removal of toxic volatile organic compounds from off gas.
Hirota, Koichi; Hakoda, Teruyuki; Taguchi, Mitsumasa; Takigami, Machiko; Kim, H.; Kojima, Takuji
Environmental Science & Technology, 37(14), p.3164 - 3170, 2003/07
Times Cited Count：45 Percentile：65.35(Engineering, Environmental)The electron-beam technology was applied to reduce polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) in flue gases from the municipal solid waste incinerator (MSWI) at a temperature of 200
C. More than 90% of PCDD/Fs in a flue gas of 1000 m
N/h was decomposed at a dose of 14 kGy. The decomposition of PCDD/Fs was probably initiated through reactions with OH radicals, followed by the dissociation of ether bond (-C-O-C-), the cleavage of aromatic rings, and dichlorination. The dechlorination of the higher dechlorinated PCDF homologues produced the lower chlorinated ones, which led to lower decomposition efficiency of PCDF than that of PCDD.
Kojima, Takuji
Oyo Butsuri, 72(4), p.405 - 414, 2003/04
The advanced technologies are required to control pollutants e.g. dioxins in gas or water at extremely low concentration. The present paper introduces typical basic studies, developments of control technologies, and example of their industrial applications of electron beam technology having the features of oxidation, decomposition and detoxifying of such pollutants even at low concentration. It covers removal of SOx and NOx from coal-combustion flue gas, decomposition of gaseous volatile organic compound in off gas and dioxins in incineration flue-gas, purification of tap and wastewaters, and treatment of sewage/sludge.
Kojima, Takuji; Hirota, Koichi; Taguchi, Mitsumasa; Hakoda, Teruyuki; Takigami, Machiko
Proceedings of 25th JAIF-KAIF Seminar on Nuclear Industry, p.193 - 201, 2003/00
The electron beam technology for decomposition/elimination of dioxin contained in flue gas has been developed using real waste gas of 1,000 mN/h released from the municipal solid waste incineration facility at 200
C. The decomposition efficiency, the ratio of toxic equivalent dioxin concentration before and after EB irradiation to doses above 15kGy is higher than 90%, which clears the regulation limit in the Japanese special measures of dioxin release. The chemical process of dioxin decomposition was studied and low-toxicity of irradiated gas was confirmed in terms of endocrine disrupter influence.
Hirota, Koichi; Hakoda, Teruyuki; Taguchi, Mitsumasa; Takigami, Machiko*; Kojima, Takuji
Proceedings of 9th International Conference on Radiation Curing (RadTech Asia '03) (CD-ROM), 4 Pages, 2003/00
The flue gas from a municipal solid waste incinerator (MSWI) was irradiated with electron beams to destroy polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). A flue gas of 1,000 m/h N for the irradiation was obtained at 200C from a main gas stream of the MSWI. The decomposition efficiencies of PCDD/Fs were increased with absorbed dose and reached 90% at a dose of 14 kGy. The reaction mechanisim for PCDD/Fs was also considered.
Ogawa, Hiroaki*; Kiuchi, Kiyoshi
JAERI-Research 2002-037, 48 Pages, 2002/12
JAERI-Research-2002-037.pdf:2.57MB
The difference in hydrogen permeation among candidate cladding materials such as 25Cr-35Ni stainless steel, Nb liner and reference materials such as 18Cr-8Ni SS, and Zr of Zircaloy base metal were evaluated by low energy plasma permeation simulated to hydrogen excited by heavy neutron irradiation. RF excitation source was arranged for the experimental apparatus in cooperating with temperature and bias control. Comparing with the thermodynamic gas driven permeation (GDP) in the same hydrogen pressure, the hydrogen permeation rate by the plasma driven permeation (PDP) was markedly accelerated at low to medium temperature range. The temperature dependency showed a knick at around 530K due to hydrogen-defect interactions. Comparing with Zr, Nb showed the high hydrogen solubility without the degradation by hydrate formation that is required to a getter material. The difference in PDP among candidates was analyzed with a new dissolution model for hydrogen.
Kotaki, Hideyuki
JAERI-Research 2002-031, 88 Pages, 2002/12
JAERI-Research-2002-031.pdf:3.33MB
We investigate a nonlinear phenomena in laser-plasma interaction, a wakefield excited by intense laser pulses, and a possibility of generating an electron beam by an intense laser pulse. Ionization of gas with a self-focusing causes a broad continuous spectrum with blueshift. The normal blueshift depends on the laser intensity and the plasma density. We have found the spectrum shifts to fixed wavelength independent of the laser power and gas pressure. We call the phenomenon "anomalous blueshift". An intense laser pulse excites a wakefield in plasma. The wakefield excited by 2TW, 50fs laser pulses in a gas-jet plasma is measured with a time-resolved frequency domain interferometer (FDI). This is the first time-resolved measurement of the wakefield of 20GeV/m in a gas-jet plasma. The FDI and the anomalous blueshift will be modified to an optical injection system as an electron beam injector. In a simulation we obtain a high quality intense electron beam. The result illuminates the possibility of a high energy and a high quality electron beam acceleration.
Igarashi, Shinichi; Muto, Shunsuke*; Tanabe, Tetsuo*; Aihara, Jun; Hojo, Kiichi
Surface & Coatings Technology, 158-159, p.421 - 425, 2002/09
no abstracts in English
) plasma-current start-up in JT-60UYoshino, Ryuji; Seki, Masami
Plasma Physics and Controlled Fusion, 39(1), p.205 - 222, 1997/01
Times Cited Count：43 Percentile：77.13(Physics, Fluids & Plasmas)no abstracts in English
Arai, Hidehiko
Hoshasen To Sangyo, 0(69), p.36 - 37, 1996/00
no abstracts in English
Haruyama, Yasuyuki; ; Ikeda, Shigetoshi*; Sunaga, Hiromi; Takizawa, Haruki; Seguchi, Tadao
JAERI-Tech 95-003, 18 Pages, 1995/02
no abstracts in English
Baba, Yuji; Yamamoto, Hiroyuki; Sasaki, Teikichi
Surface Science, 287-288, p.806 - 810, 1993/00
Times Cited Count：10 Percentile：51.83(Chemistry, Physical)no abstracts in English
Baba, Yuji; G.Dujardin*; P.Feulner*; D.Menzel*
Hyomen Kagaku, 13(5), p.244 - 248, 1992/07
no abstracts in English
Baba, Yuji; Yamamoto, Hiroyuki; Sasaki, Teikichi
Nuclear Instruments and Methods in Physics Research B, 66, p.424 - 432, 1992/00
Times Cited Count：8 Percentile：63.56(Instruments & Instrumentation)no abstracts in English
