Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 44

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Progress of divertor simulation research toward the realization of detached plasma using a large tandem mirror device

Nakashima, Yosuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Oki, Kensuke*; Sakamoto, Mizuki*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; Imai, Tsuyoshi*; et al.

Journal of Nuclear Materials, 463, p.537 - 540, 2015/08

 Times Cited Count:17 Percentile:9.39(Materials Science, Multidisciplinary)

Journal Articles

Development of a prototype GEM TPC with a gating grid for an H-dibaryon search experiment at J-PARC

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:4 Percentile:60.77(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$$_{4}$$ (90:10) and Ar-CF$$_{4}$$ (95:5), where the former is mainly used. The detection efficiency was measured to be 98% at the beam rate up to $$5times10^{5}$$ cps/cm$$^{2}$$, and 90% at the rate of $$3times10^{6}$$ cps/cm$$^{2}$$. 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 $$1.6times10^{4}$$. The horizontal position distortion due to ion backflow in the gate operation was suppressed within $$pm 0.2$$ mm at the beam rates up to $$5times10^{5}$$ cps/cm$$^{2}$$. On the other hand, the distortion with the gate open was measured to be $$pm2$$ mm. The distortion in the final experiment is estimated to be $$0.3 pm 0.2$$ mm.

Journal Articles

Development of divertor simulation research in the GAMMA 10/PDX tandem mirror

Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10

Journal Articles

Development of a GEM-TPC for H-dibaryon search experiment at J-PARC

Sako, Hiroyuki; Ahn, J. K.*; Baek, K. H.*; Bassalleck, B.*; Fujioka, H.*; Guo, L.*; Hasegawa, Shoichi; Hicks, K.*; Honda, R.*; Hwang, S. H.*; et al.

Journal of Instrumentation (Internet), 9(4), p.C04009_1 - C04009_10, 2014/04

 Times Cited Count:3 Percentile:79.72(Instruments & Instrumentation)

A TPC has been developed for J-PARC E42 experiment to search for H-dibaryon in ($$K^-$$, $$K^+$$) reaction. An event with 2 $$pi^-$$ and 2 protons decaying from H-dibaryon is searched for inside the TPC. The TPC has octagonal prism shape drift volume with about 50 cm diameter with 55 cm drift length filled with Ar-CH$$_{4}$$ (90:10) gas. At the end of the drift volume, 3-layer GEMs are equipped. In order to analyze momenta of produced particles, the TPC is applied with 1 T dipole magnetic field parallel to the drift electric field with a superconducting Helmholz magnet. In order to maximize the acceptance of H-dibaryon events, a diamond target is installed inside the TPC drift volume, in a cylindrical hole opened from the top to the middle of the drift volume. Since extremely high-rate $$K^-$$ beam is directly injected into the TPC drift volume to the target, a gating grid and GEMs are adopted to suppress positive-ion feedback.

Journal Articles

Search for $$^6_{Lambda}$$H hypernucleus by the $$^{6}$$Li($$pi^-,K^+$$) reaction at $$p_pi$$- = 1.2 GeV/$$c$$

Sugimura, Hitoshi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Kiuchi, Ryuta; Ichikawa, Yudai; Hwang, S. H.*; Hasegawa, Shoichi; Tanida, Kiyoshi; J-PARC E10 Collaboration*

Physics Letters B, 729, p.39 - 44, 2014/02

 Times Cited Count:26 Percentile:11.47(Astronomy & Astrophysics)

We have carried out an experiment to search for a neutron-rich hypernucleus, $$^6_Lambda$$H, by the $$^{6}$$Li($$pi$$$$^{-}$$,K$$^{+}$$) reaction at p$$_{pi-}$$ = 1.2 GeV/c. The obtained missing-mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the $$^6_Lambda$$H hypernucleus neither below nor above the $$^4_Lambda$$H+2n particle decay threshold. An upper limit of the production cross section for the bound $$^6_Lambda$$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.

Journal Articles

Development of a high power gyrotron operating at 28 and 35 GHz

Kariya, Tsuyoshi*; Minami, Ryutaro*; Imai, Tsuyoshi*; Eguchi, Taku*; Sakamoto, Keishi; Mitsunaka, Yoshika*; Numakura, Tomoharu*; Endo, Yoichi*

Plasma and Fusion Research (Internet), 8, p.1205107_1 - 1205107_2, 2013/10

Journal Articles

J-PARC E27 experiment to search for a nuclear Kaon bound state $$K^-pp$$

Imai, Kenichi; Ichikawa, Yudai; Hasegawa, Shoichi; Sako, Hiroyuki; Sato, Susumu; Kiuchi, Ryuta*; Hosomi, Kenji; Sugimura, Hitoshi; 36 of others*

Few-Body Systems, 54(7-10), p.1191 - 1194, 2013/08

 Times Cited Count:9 Percentile:41.19(Physics, Multidisciplinary)

In the J-PARC E27 experiment, we search for a $$K^-pp$$ bound state via the $$d(pi^{+}, K^+)$$ reaction at 1.7 GeV/c at the K1.8 beam line. The binding energy and decay width of the $$K^-pp$$ bound state can be obtained in the missing mass measurement with a good energy resolution of 2 MeV/c$$^2$$. A range counter array (RCA) was constructed to detect the two high-momentum protons from the $$K^-pp$$ decay and to reduce the background such as quasi-free hyperon production. Recently, we have carried out a pilot run in June, 2012. The $$d(pi^{+}, K^+)$$ missing-mass spectrum has been obtained for the first time.

Journal Articles

Development of multi-purpose MW gyrotrons for fusion devices

Minami, Ryutaro*; Kariya, Tsuyoshi*; Imai, Tsuyoshi*; Numakura, Tomoharu*; Endo, Yoichi*; Nakabayashi, Hidetaka*; Eguchi, Taku*; Shimozuma, Takashi*; Kubo, Shin*; Yoshimura, Yasuo*; et al.

Nuclear Fusion, 53(6), p.063003_1 - 063003_7, 2013/06

Journal Articles

Development of multi-purpose MW gyrotrons for fusion devices

Minami, Ryutaro*; Kariya, Tsuyoshi*; Imai, Tsuyoshi*; Numakura, Tomoharu*; Endo, Yoichi*; Nakabayashi, Hidetaka*; Eguchi, Taku*; Shimozuma, Takashi*; Kubo, Shin*; Yoshimura, Yasuo*; et al.

Nuclear Fusion, 53(6), p.063003_1 - 063003_7, 2013/06

 Times Cited Count:12 Percentile:43.03(Physics, Fluids & Plasmas)

Journal Articles

Development of silicon strip detector for the measurement of the $$Xi$$-atom X-rays

Sugimura, Hitoshi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Adachi, Satoshi*; Tanida, Kiyoshi*; Kiuchi, Ryuta*; Joo, C. W.*

AIP Conference Proceedings 1388, p.602 - 604, 2011/10

 Times Cited Count:0 Percentile:100

no abstracts in English

Journal Articles

Development of 28 GHz and 77 GHz 1 MW gyrotron for ECRH of magnetically confined plasma

Kariya, Tsuyoshi*; Minami, Ryutaro*; Imai, Tsuyoshi*; Sakamoto, Keishi; Kubo, Shin*; Shimozuma, Takashi*; Takahashi, Hiromi*; Ito, Satoshi*; Muto, Takashi*; Mitsunaka, Yoshika*; et al.

Fusion Science and Technology, 55(2T), p.91 - 94, 2009/02

 Times Cited Count:11 Percentile:35.71(Nuclear Science & Technology)

JAEA Reports

Development of SO$$_{3}$$ decomposer for thermochemical hydrogen production by IS process; Basic design of SiC plate-type SO$$_{3}$$ decomposer and catalyst test results

Kanagawa, Akihiro; Imai, Yoshiyuki; Terada, Atsuhiko; Onuki, Kaoru; Hino, Ryutaro

JAEA-Technology 2007-043, 54 Pages, 2007/09

JAEA-Technology-2007-043.pdf:27.01MB

Thermo-chemical Iodine-Sulfur (IS) process has a potential to produce large amount of hydrogen without CO$$_{2}$$ emission by using thermal energy of a high temperature gas-cooled reactor (HTGR). In SO$$_{3}$$ decomposer of IS process, SO$$_{3}$$ gas is catalytically decomposed into O$$_{2}$$ and SO$$_{2}$$ under high temperature condition up to 850$$^{circ}$$C using the sensible heat of He gas. The decomposer is exposed to the severe corrosive condition. We proposed a new concept of the decomposer, which featured a plate-type heat exchanger made of SiC ceramics and revealed the results of thermal-hydraulic and mechanical strength analysis. To examine the fabricability of the proposed concept, a mock-up model was test-fabricated and issues on the fabricability of large-sized decomposer were clarified. Also, preliminary catalyst tests were carried out to clarify catalyst bed specification of the SO$$_{3}$$ decomposer.

Journal Articles

Upgrade program of ECRH system for GAMMA10

Imai, Tsuyoshi*; Tatematsu, Yoshinori*; Numakura, Tomoharu*; Sakamoto, Keishi; Minami, Ryutaro*; Watanabe, Osamu*; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Kamata, Yasuhiro*; Machida, Norihito*; et al.

Fusion Science and Technology, 51(2T), p.208 - 212, 2007/02

 Times Cited Count:9 Percentile:41.26(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Optimization of 28GHz gyrotron output performance for ECRH experiment of the GAMMA 10

Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Imai, Tsuyoshi*; Saito, Teruo*; Tatematsu, Yoshinori*; Sakamoto, Keishi; Minami, Ryutaro*; Watanabe, Osamu*; Numakura, Tomoharu*; Endo, Yoichi*

Fusion Science and Technology, 51(2T), p.397 - 399, 2007/02

 Times Cited Count:8 Percentile:45.16(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Characteristics of 28 GHz gyrotron for ECRH on GAMMA10

Kamata, Yasuhiro*; Imai, Tsuyoshi*; Tatematsu, Yoshinori*; Watanabe, Osamu*; Minami, Ryutaro*; Saito, Teruo*; Sakamoto, Keishi; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Machida, Norihito*; et al.

Fusion Science and Technology, 51(2T), p.412 - 414, 2007/02

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Development program of IS process pilot test plant for hydrogen production with high-temperature gas-cooled reactor

Iwatsuki, Jin; Terada, Atsuhiko; Noguchi, Hiroki; Imai, Yoshiyuki; Ijichi, Masanori; Kanagawa, Akihiro; Ota, Hiroyuki; Kubo, Shinji; Onuki, Kaoru; Hino, Ryutaro

Proceedings of 14th International Conference on Nuclear Engineering (ICONE-14) (CD-ROM), 8 Pages, 2006/07

JAEA has been conducting the HTTR project from the view to establishing technology base on HTGR and also on the IS process. Based on the test results and know-how obtained through the bench-scale tests, a pilot test plant that can produce hydrogen of about 30 Nm$$^{3}$$/hr is being designed. The test plant will be fabricated with industrial materials such as glass coated steel, SiC ceramics etc, and operated under high pressure condition up to 2 MPa. The test plant will consist of a IS process plant and a helium gas (He) circulation facility (He loop). In parallel to the design study, key components of the IS process such as the sulfuric acid (H$$_{2}$$SO$$_{4}$$) and the sulfur trioxide (SO$$_{3}$$) decomposers working under-high temperature corrosive environments have been designed and test-fabricated to confirm their fabricability. Also, other R&D's are under way such as corrosion, processing of HIx solutions. This paper describes present status of these activities.

Journal Articles

Development of reliable diamond window for EC launcher on fusion reactors

Takahashi, Koji; Illy, S.*; Heidinger, R.*; Kasugai, Atsushi; Minami, Ryutaro; Sakamoto, Keishi; Thumm, M.*; Imai, Tsuyoshi

Fusion Engineering and Design, 74(1-4), p.305 - 310, 2005/11

 Times Cited Count:13 Percentile:31(Nuclear Science & Technology)

A new diamond window with the copper-coated edge for an EC launcher is developed. The diamond window is designed to cool its disk edge. Since Cu is coated at the entire edge, ingress of cooling water into a transmission line in case of failure on the edge is negligible. In addition, corrosion of Al blaze between the edge and the Inconel cuffs can be avoided. A 170GHz, RF transmission experiment equivalent to a MW-level transmission was carried out to investigate the capability of the edge cooling. The transmission power and pulse are 55kW and 3sec, respectively. Temperature increase was 45$$^{circ}$$C and alomost became constant. Thermal calculation with tan$$delta$$ of 4.4$$times$$10$$^{-4}$$ and thermal conductivity of 1.9kW/m/K agrees with the experiment. Since tan$$delta$$ of the diamond is much higher than the actual one (tan$$delta$$=2$$times$$10$$^{-5}$$), the temperature increase corresponds to that of 1MW transmission. It concludes that the Cu coating dose not degrade the edge cooling capability and improves the reliability of the diamond window.

Journal Articles

Study of millimeter wave high-power gyrotron for long pulse operation

Kasugai, Atsushi; Sakamoto, Keishi; Minami, Ryutaro; Takahashi, Koji; Imai, Tsuyoshi

Nuclear Instruments and Methods in Physics Research A, 528(1-2), p.110 - 114, 2004/08

 Times Cited Count:23 Percentile:17.36(Instruments & Instrumentation)

The development of the millimeter wave high power gyrotron with the development of a depressed collector, an over sized cavity and a synthesized diamond output window is under going in JAERI. The performances of 170 GHz, 0.9 MW for 9.2 s and 0.5 MW for 30 s were achieved up to now. It was clarified, however, that pulse extension of the gyrotron was limited by sudden outgassing due to stray RF power deposition to the bellows behind movable mirror. For suppression of stray RF power deposition, the structure of the bellows section was improved to avoid the direct power deposition and the surface of bellows was coated by copper for reduction of RF loss and increase of thermal conductivity. As a result of the modification, temperature increase of bellows was reduced to less than 1/10 and time constant of thermal diffusion shortened to 90 s from 270 s in comparison with before the modification. This indicates that the modification is quite effective for suppression of temperature increase.

JAEA Reports

Control of electron beam current of high power gyrotron for CW operation

Minami, Ryutaro; Kobayashi, Noriyuki*; Sakamoto, Keishi; Kasugai, Atsushi; Takahashi, Koji; Imai, Tsuyoshi

JAERI-Research 2004-006, 17 Pages, 2004/03

JAERI-Research-2004-006.pdf:1.37MB

no abstracts in English

Journal Articles

Removal and recovery of uranium from solid wastes by supercritical carbon dioxide fluid leaching method

Meguro, Yoshihiro; Tomioka, Osamu; Imai, Tomoki*; Fujimoto, Shigeyuki*; Nakashima, Mikio; Yoshida, Zenko; Honda, Tadashi*; Koya, Fumio*; Kitamura, Nobu*; Wada, Ryutaro*; et al.

Proceedings of International Waste Management Symposium 2004 (WM '04) (CD-ROM), 8 Pages, 2004/03

Supercritical CO$$_{2}$$ fluid leaching (SFL) method using supercritical CO$$_{2}$$ fluid containing a complex of HNO$$_{3}$$ - tri-n-butyl phosphate (TBP) was applied to removal of uranium from radioactive solid wastes. Sea sands, incineration ashes and porous alumina bricks were employed as matrixes of simulated solid wastes. Real radioactive incineration ash wastes and firebrick wastes were also subjected to the SFL treatment. It was found that uranium could be efficiently removed from both of the simulated wastes and real wastes by the SFL method. The removal efficiency of uranium from the real waste was lower than that from the corresponding artificial waste. About 1 g and 35 mg of uranium were recovered from 10 g of the real ash waste and 37 g of the real firebrick waste, respectively.

44 (Records 1-20 displayed on this page)