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Journal Articles

Evaluation of DNA lesions induced by high-let ion beams using quantitative polymerase chain reaction

Matsuo, Yoichiro*; Izumi, Yoshinobu*; Hase, Yoshihiro; Sakamoto, Ayako; Shimizu, Kikuo*

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 104, 2016/02

no abstracts in English

Journal Articles

Measurement of ion beam induced current in quantum dot solar cells

Nakamura, Tetsuya*; Imaizumi, Mitsuru*; Sato, Shinichiro; Sugaya, Takeyoshi*; Mochizuki, Toru*; Okano, Yoshinobu*; Oshima, Takeshi

Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.73 - 76, 2015/11

The radiation effect on GaAs p-i-n solar cells with quantum dot (QD) in the i-layer was investigated. In a previous work, we particularly noted the degradation of fill-factor (FF) for the QD cells. In this work, to clarify the reason of the FF degradation in QD cells, generation current due to low-energy proton irradiation, which we call ion beam induced current (IBIC), was observed to characterize behavior of the generated minority carrier by the protons in the depletion region where QDs are located. The energy of protons was adjusted to damage the depletion region, and decrease of generation current was measured during the proton irradiation. The results suggest that the serious degradation of FF is caused by a decrease of the carrier collection efficiency in the depletion region due to proton damage.

Journal Articles

Development of laser welding technology for fully austenite stainless steel

Takano, Katsutoshi; Koizumi, Norikiyo; Serizawa, Hisashi*; Tsubota, Shuho*; Makino, Yoshinobu*

Yosetsu Gakkai Rombunshu (Internet), 33(2), p.126 - 132, 2015/06

A radial plates (RP), which is used in Toroidal field (TF) coil in ITER, is significantly large, such as 13 m height and 9 m wide, but thin, such as 10 cm thick, and are made of full-austenite stainless steel. Even though they are very large structures, high manufacturing tolerances are required. In addition, it is required that each RP is fabricated every three weeks. Therefore, the authors develop efficient manufacturing methods of RP. The laser welding is selected as a welding method of RP. But the development of the high power laser welding technology is necessary to avoid hot cracking of the materials used for RP, namely full austenite stainless steel with high nitrogen content. The authors carried out trial aiming at an application of the laser welding to RP. As a result, it is effective to optimize the angle of inclination of the weld head. It also seems sensitivity of hot cracking can be less by optimizing the chemical composition of materials to use for RP. It was therefore demonstrated that the application of the laser welding technology in the full austenite stainless steel.

Journal Articles

Molecular analysis of heavy ion induced mutations in budding yeast ${it S. cerevisiae}$

Matsuo, Yoichiro*; Izumi, Yoshinobu*; Hase, Yoshihiro; Sakamoto, Ayako; Shimizu, Kikuo*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 119, 2015/03

no abstracts in English

Journal Articles

Molecular analysis of heavy ion induced mutations in budding yeast ${it S. cerevisiae}$

Matsuo, Yoichiro*; Izumi, Yoshinobu*; Hase, Yoshihiro; Sakamoto, Ayako; Nozawa, Shigeki; Narumi, Issey*; Shimizu, Kikuo*

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 112, 2014/03

Journal Articles

DNA damage evaluation system of the high-LET ion beam using the polymerase chain reaction

Matsuo, Yoichiro*; Izumi, Yoshinobu*; Hase, Yoshihiro; Sakamoto, Ayako; Nozawa, Shigeki; Narumi, Issei; Shimizu, Kikuo*

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 105, 2013/01

Journal Articles

Development of ITER TF coil in Japan

Koizumi, Norikiyo; Matsui, Kunihiro; Hemmi, Tsutomu; Takano, Katsutoshi; Chida, Yutaka; Iguchi, Masahide; Nakajima, Hideo; Shimada, Mamoru*; Osemochi, Koichi*; Makino, Yoshinobu*; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4200404_1 - 4200404_4, 2012/06

 Times Cited Count:8 Percentile:46.26(Engineering, Electrical & Electronic)

JAEA started sub- and full-scale trials to qualify and optimize manufacturing procedure of ITER TF coil from March, 2009. As major outcome of these trials, automatic winding system with accuracy in conductor length measurement of 0.01% has been established and the elongation of the conductor length due to heat treatment was measured to be 0.06%. To confirm validity of these outcomes, the authors carried out winding of a one-third scale dummy double pancake (DP), followed by its insulation and impregnation trial, and, in addition, heat treatment of one-third scale DP with real a TF conductor. The details about these trials are described in the other paper. The authors also performed trial manufacture of full scale RP and CPs for dummy double pancake, which will be made in near future. The full scale RP is manufactured by machining 10 segments in parallel to shorten machining duration and joining each segment by welding. In our trial manufacture of the full scale RP, hot-rolled SS316LN plates are machined to a final dimension, namely without additional material, and these segments are laser-welded. From these trials, manufacturing procedure of a thick hot-roll SS316LN plate is qualified and machining procedure is established, while more optimization may be necessary to achieve the required schedule and cost.

Journal Articles

Simulation of radioactive corrosion product in primary cooling system of Japanese sodium-cooled fast breeder reactor

Matsuo, Yoichiro; Miyahara, Shinya; Izumi, Yoshinobu*

Journal of Power and Energy Systems (Internet), 6(1), p.6 - 17, 2012/03

Radioactive corrosion product (CP) is a main cause of personal radiation exposure during maintenance with no breached fuel in fast breeder reactor (FBR) plants. In order to establish techniques of radiation dose estimation for radiation workers in radiation-controlled areas of the FBR, the PSYCHE (Program SYstem for Corrosion Hazard Evaluation) code was developed. We add the Particle Model to the conventional PSYCHE analytical model. In this paper, we performed calculation of CP transfer in JOYO using an improved calculation code in which the Particle Model was added to the PSYCHE code. The C/E (calculated / experimentally observed) value for CP deposition was improved through use of this improved PSYCHE code incorporating the Particle Model.

Journal Articles

Results of ITER toroidal field coil cover plate welding test

Koizumi, Norikiyo; Matsui, Kunihiro; Shimizu, Tatsuya; Nakajima, Hideo; Iijima, Ami*; Makino, Yoshinobu*

Teion Kogaku, 47(3), p.186 - 192, 2012/03

In the ITER TF coil, cover plates (CP) are welded to teeth of a radial plate (RP) to fix a conductor in the groove of the RP. Though total length of welds is approximately 1.5 km and height and width of an RP are 14 m and 9 m, respectively, the welding deformation better than 1 mm in local distortion and several milli-meters in in-plane deformation is required. Therefore, laser welding is used for the CP welding to reduce welding deformation as possible. However, a gap of a welding joint is expected to be 0.5 mm at the maximum. Therefore, at first, the laser welding technique to enable welding on the gap of 0.5 mm width is developed in this study. Using this technology, CP welding trial using an RP mock was successfully performed. The achieved flatness is 0.6 mm. In addition, the welding deformation of a full-scale RP is estimated by the analysis using the inherent strain. The results show that the flatness of 1 mm is achievable and profile of 5 mm can be achieved. Since the in-plane deformation can be corrected by welding somewhere to originate artificial welding deformation, it is confident that the required tolerance of several milli-meters in in-plan profile is achievable.

Journal Articles

Trial manufacture of ITER toroidal field coil radial plate

Takano, Katsutoshi; Koizumi, Norikiyo; Shimizu, Tatsuya; Nakajima, Hideo; Esaki, Koichi*; Nagamoto, Yoshifumi*; Makino, Yoshinobu*

Teion Kogaku, 47(3), p.178 - 185, 2012/03

In the ITER TF coil, the tight tolerances of 1 mm in flatness and a few mm in profile are required in manufacturing a radial plate (RP), although the height and width of an RP are 13 m and 9 m, respectively. In addition, since cover plates (CP) should be fitted to a groove of an RP with tolerance of 0.5 mm, the tight tolerances are also required to a CP. Thus, we can conclude that the manufacturing procedure of the RP and CP has been demonstrated.

Journal Articles

Fundamental study on molecular mechanism underlying repair of heavy-ion induced DNA damage in the ${it Saccharomyces cerevisiae}$

Matsuo, Yoichiro*; Izumi, Yoshinobu*; Hase, Yoshihiro; Sakamoto, Ayako; Nozawa, Shigeki; Narumi, Issei; Shimizu, Kikuo*

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 108, 2012/01

Journal Articles

Proposed method of the modeling and simulation of corrosion product behavior in the primary cooling system of fast breeder reactors

Matsuo, Yoichiro; Miyahara, Shinya; Izumi, Yoshinobu*

Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 8 Pages, 2011/10

In order to establish the techniques of radiation dose estimation for worker in radiation-controlled area, PSYCHE code has been developed. The PSYCHE is based on the Solution-Precipitation model. The CP transfer calculation using the Solution-Precipitation model needs a fitting factor for the calculation of the precipitation of CP. In this study, in addition to existing Solution-Precipitation model in PSYCHE, a transfer-model of CP species in particle form was applied to calculations of CP behavior in the primary cooling system of fast breeder reactor MONJU. Based on the calculated results, we estimated the contribution of CP deposition in the particle-form. It was suggested that the improved model including transfer-model of CP species in particle-form could be used for evaluation of CP transfer and radiation-source distribution in place of conventional Solution-Precipitation model with fitting factor in the PSYCHE.

Journal Articles

Molecular analysis of carbon ion induced mutations in yeast ${it Saccharomyces cerevisiae}$ cells

Shimizu, Kikuo*; Matsuo, Yoichiro*; Izumi, Yoshinobu*; Hase, Yoshihiro; Nozawa, Shigeki; Sakamoto, Ayako; Narumi, Issei

JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 79, 2011/01

Journal Articles

Fission neutron irradiation effect on interlaminar shear strength of cyanate ester resin GFRP at RT and 77 K

Nishimura, Arata*; Izumi, Yoshinobu*; Nishijima, Shigehiro*; Hemmi, Tsutomu; Koizumi, Norikiyo; Takeuchi, Takao*; Shikama, Tatsuo*

AIP Conference Proceedings 1219, p.127 - 134, 2010/04

 Times Cited Count:1 Percentile:51.8

A GFRP with cyanate ester resin was fabricated and neutron irradiation tests up to 1$$times$$10$$^{22}$$ n/m$$^{2}$$ of fast neutron with over 0.1 MeV energy were carried out in fission reactor. The fabrication process of cyanate ester GFRP was established and a collaboration network to perform investigations on irradiation effect of superconducting magnet materials was constructed. Three kinds of samples were fabricated. The first was CTD403 GFRP made by NIFS, the second was (cyanate ester + epoxy) GFRP provided by Toshiba, and the last was CTD403 GFRP made by Toshiba. The irradiation was carried out at JRR-3 in Japan Atomic Energy Agency using Rabbit capsules. After the irradiation, short beam tests were conducted at room temperature and 77 K and interlaminar shear strength (ILSS) was evaluated. The irradiation of 1$$times$$10$$^{21}$$ n/m$$^{2}$$ increased ILSS a little but 1$$times$$10$$^{22}$$ n/m$$^{2}$$ irradiation decreased ILSS to around 50 MPa. These tendencies were observed in all three kinds of GFRPs.

Journal Articles

Laser-arc hybrid welding for the cover plate of ITER TF coil

Shiihara, Katsunori*; Makino, Yoshinobu*; Ogawa, Tsuyoshi*; Asai, Satoru*; Kanahara, Toshio*; Senda, Ikuo*; Okuno, Kiyoshi; Koizumi, Norikiyo; Matsui, Kunihiro

Proceedings of 26th International Congress on Applications of Lasers & Electro-Optics (ICALEO 2007) (CD-ROM), p.316 - 324, 2007/10

The toroidal field coil is manufactured as one of superconducting coil systems in the ITER. For welding the cover plate of TF coil, the prevention of the thermal effect on the coil and the deformation of the whole coil are required. Moreover, the application of high efficient welding is required in consideration for the productivity. Therefore, laser-arc hybrid welding process was investigated for the application to the cover plate welding, because its process is superior in the tolerance of the joint gap and the ease of the control for the heat input. In the experiment, it was confirmed that the application of laser-arc hybrid welding with the double gas shielding for high concentration arc and the filler wire for controlling the deposit amount is effective in the joint gap up to 0.8mm. Besides, twin spot laser head with the arc was developed in order to weld the both sides of cover plate simultaneously. By the optimization of welding condition for twin spot laser-arc hybrid welding process, it was confirmed to be effective in the prevention of the gap movement during welding and the acquisition of the proper penetration without the weld defect. Finally, the effectiveness of laser-arc hybrid welding for the welding deformation and the weldability on the quality was verified by the scale model test with the actual shape.

Journal Articles

Influence of diluent on radiolysis of amides in organic solution

Sugo, Yumi; Izumi, Yoshinobu*; Yoshida, Yoichi*; Nishijima, Shigehiro*; Sasaki, Yuji; Kimura, Takaumi; Sekine, Tsutomu*; Kudo, Hiroshi*

Radiation Physics and Chemistry, 76(5), p.794 - 800, 2007/05

 Times Cited Count:69 Percentile:97.42(Chemistry, Physical)

The radiolytic behavior of ${it N,N,N',N'}$-tetraoctyldiglycolamide, ${it N,N'}$-dimethyl-${it N,N'}$-dioctyl-2-(3'-oxapentadecyl)malonamide, and ${it N,N}$-dioctylhexanamide in ${it n}$-dodecane was investigated by irradiation with $$gamma$$-rays and electron pulses. The results showed ${it n}$-dodecane has a sensitization effect on the radiolysis of these amides, owing mainly to a charge transfer from radical cations of ${it n}$-dodecane to the amide molecules in the primary process observed in pulse radiolysis.

Journal Articles

Monte Carlo simulation of strand position in CIC Conductor

Aoki, Kosuke*; Izumi, Yoshinobu*; Nishijima, Shigehiro*; Okuno, Kiyoshi; Koizumi, Norikiyo

IEEE Transactions on Applied Superconductivity, 13(2), p.1744 - 1747, 2003/06

 Times Cited Count:1 Percentile:12.58(Engineering, Electrical & Electronic)

The strand position in CIC conductor consisting of 1,152(3$$times$$4$$times$$4$$times$$4$$times$$6) strands was analytically evaluated using Monte Carlo method. During the conductor fabrication, the conduit was compressed with the cable to fix the size and shape from one end. This makes the strands to be stretched along the axis. In the calculation, such manufacturing process was simulated. In addition, the contact energy between strands and the strain energy in the strands are considered. The calculation results show that the strands are moved by compressing the conduit. By this calculation, not only strand positions but also the distribution of contact stress between strands could be evaluated.

Journal Articles

Gelation mechanism of atactic polystyrene/carbon disulfide as revealed by neutron diffraction

Izumi, Yoshinobu*; Suzuki, Junichi; Katano, Susumu; Funahashi, Satoru

Physica B; Condensed Matter, 213-214, p.724 - 726, 1995/00

 Times Cited Count:5 Percentile:37.07(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Structure of physical gels formed in syndiotactic polystyrene/solvent systems studied by small-angle neutron scattering

Kobayashi, Masamichi*; Yoshioka, Toshimori*; Kozasa, Takehiko*; Tashiro, Koji*; Suzuki, Junichi; Funahashi, Satoru; Izumi, Yoshinobu*

Macromolecules, 27(6), p.1349 - 1354, 1994/00

 Times Cited Count:42 Percentile:84.75(Polymer Science)

no abstracts in English

Journal Articles

Generation of organic ion beams having an amino functional group

Tamada, Masao; Izumi, Yoshinobu; Omichi, Hideki

Radiation Physics and Chemistry, 43(3), p.303 - 305, 1993/00

 Times Cited Count:0 Percentile:0.67(Chemistry, Physical)

no abstracts in English

42 (Records 1-20 displayed on this page)