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Tomizawa, Hiromitsu*; Sato, Takahiro*; Ogawa, Kanade*; Togawa, Kazuaki*; Tanaka, Takatsugu*; Hara, Toru*; Yabashi, Makina*; Tanaka, Hitoshi*; Ishikawa, Tetsuya*; Togashi, Tadashi*; et al.
High Power Laser Science and Engineering, 3, p.e14_1 - e14_10, 2015/04
Times Cited Count：6 Percentile：34.43(Optics)no abstracts in English
Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Togashi, Tadashi*; Fukami, Kenji*; et al.
Journal of Physics B; Atomic, Molecular and Optical Physics, 46(16), p.164006_1 - 164006_6, 2013/08
Times Cited Count：3 Percentile：19.06(Optics)By introducing 13th- (61.7 nm) and 15th-order harmonics (53.4 nm) of femtosecond laser pulses at 800 nm into an undulator of SCSS (SPring-8 Compact SASE Source) test accelerator at RIKEN, these harmonic pulses were amplified by a factor of more than 10
with a high contrast ratio through the interaction between accelerated electron bunches and the harmonic pulses. From numerical simulations of the amplification processes of high-order harmonic pulses in the undulator, optimum conditions of the electron bunch duration interacting with the high-order harmonic pulses were investigated for generating full-coherent and intense pulses in the extreme ultraviolet wavelength region.
Ogawa, Kanade*; Sato, Takahiro*; Matsubara, Shinichi*; Okayasu, Yuichi*; Togashi, Tadashi*; Watanabe, Takahiro*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; et al.
Proceedings of 10th Conference on Lasers and Electro-Optics Pacific Rim and 18th OptoElectronics and Communications Conference and Photonics in Switching 2013 (CLEO-PR & OECC/PS 2013) (USB Flash Drive), 2 Pages, 2013/06
no abstracts in English
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; et al.
Proceedings of Ultrafast Optics IX (CD-ROM), 2 Pages, 2013/03
We have demonstrated free-electron laser radiation seeded by high-order harmonics in the extreme-ultraviolet region. Strong enhancement of the radiation intensity by a factor of 104 was observed with timing control of an electro-optical sampling technique.
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; et al.
Proceedings of 11th International School and Symposium on Synchrotron Radiation in Natural Science (ISSRNS 2012), p.1 - 21, 2012/05
The 13th harmonic of a Ti:sapphire laser has been significantly amplified with the SCSS test accelerator. The temporal and spatial overlap of the electron beam and the high harmonic radiation were precisely tuned for achieving the seeded free electron laser operation. With numerical simulation the present HH-seeded FEL scheme could readily be applied to the wavelength region down to 10 nm.
Takahashi, Eiji*; Togashi, Tadashi*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; et al.
Proceedings of European Conference on Lasers and Electro-Optics and the 12th European Quantum Electronics Conference (CLEO/Europe-EQEC 2011) (CD-ROM), 1 Pages, 2011/05
We succeeded in generating the seeded free electron laser (FEL) with wavelengths of 61 nm at the SCSS test accelerator. The 13th (61 nm) harmonics generated by focusing the high peak power Ti:Sapphire laser to the Xe gas cell was directed to the undulator. This is first realization of the seeded FEL in extreme ultraviolet region.
Takahashi, Eiji*; Togashi, Tadashi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; Matsubara, Shinichi*; et al.
Proceedings of International Quantum Electronics Conference and the Pacific Rim Conference on Lasers and Electro-Optics (IQEC/CLEO Pacific Rim 2011) (CD-ROM), p.199 - 200, 2011/05
We succeeded in generating the seeded free electron laser (FEL) with wavelengths of 61 nm at the SCSS test accelerator. The 13th (61 nm) harmonics generated by focusing the high peak power Ti:Sapphire laser to the Xe gas cell was directed to the undulator. This is first realization of the seeded FEL in extreme ultraviolet region.
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Okino, Tomoya*; Yamanouchi, Kaoru*; et al.
Optics Express (Internet), 19(1), p.317 - 324, 2011/01
Times Cited Count：96 Percentile：96.45(Optics)The 13th harmonic of a Ti:sapphire (Ti:S) laser in the plateau region was injected as a seeding source to a 250-MeV free-electron-laser (FEL) amplifier. When the amplification conditions were fulfilled, strong enhancement of the radiation intensity by a factor of 650 was observed. The random and uncontrollable spikes, which appeared in the spectra of the Self-Amplified Spontaneous Emission (SASE) based FEL radiation without the seeding source, were found to be suppressed drastically to form to a narrow-band, single peak profile at 61.2 nm. The properties of the seeded FEL radiation were well reproduced by numerical simulations. We discuss the future precept of the seeded FEL scheme to the shorter wavelength region.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*; Hibiya, Keisuke*; Yokozeki, Kosuke*; Watanabe, Kenzo*
JNC TJ8400 2003-047, 120 Pages, 2003/02
JNC-TJ8400-2003-047.pdf:4.46MB
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or immersing as the fundamental data.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*; Hibiya, Keisuke*; Yokozeki, Kosuke*; Watanabe, Kenzo*
JNC TJ8400 2003-046, 282 Pages, 2003/02
JNC-TJ8400-2003-046.pdf:8.26MB
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or immersing as the fundamental data.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*
JNC TJ8400 2003-042, 67 Pages, 2003/02
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. In this study, we estimated the influence of sodium nitrate and also that of the chemical compounds derived from the sodium nitrate to the degradation of the cementitious material. 1) Evaluation of the influence of nitrate ion on the alteration of the cementitious material Alteration of characteristics of cementitious material was evaluated by the water permeation test using sodium nitrate solution. The calcium concentration of sodium nitrate solution permeated sample was higher than that of blank. The result indicates that sodium nitrate solution will accelerate the alteration of cementitious material. the permeation test was continued by using the ion-exchanged water as the permeation-water. As the results, the chemical and physical characteristics of the samples approached to those of blanks.2) Evaluation of the influence of ammonia on the alteration of the cementitious material Alteration of characteristics of cementitious material in nitrate and ammonia solution was evaluated by the water permeation test using 1mol/liter-sodium-nitrate and 0.5mol/liter-ammonia solution (denoted as NH-solution in the following). The calcium concentration of NH-solution permeated sample was higher than that of blank and the value of the calcium concentration was almost the same as that of the sodium nitrate solution case. The alteration range by the calcium leaching of the solid phase of the NH-solution case shows similar trend to that of the sodium nitrate solution case. The acceleration of the calcium dissolution was considered from this result. And the change of the water-permeability indicated the same trend with sodium-nitrate-solution case. From these results we confirmed that ammonia solution would not influence the alteration of cementitious solution.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*
JNC TJ8400 2003-041, 152 Pages, 2003/02
JNC-TJ8400-2003-041.pdf:7.93MB
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. In this study, we estimated the influence of sodium nitrate and also that of the chemical compounds derived from the sodium nitrate to the degradation of the cementitious material. 1) Evaluation of the influence of nitrate ion on the alteration of the cementitious material Alteration of characteristics of cementitious material was evaluated by the water permeation test using sodium nitrate solution. The calcium concentration of sodium nitrate solution permeated sample was higher than that of blank. The result indicates that sodium nitrate solution will accelerate the alteration of cementitious material. the permeation test was continued by using the ion-exchanged water as the permeation-water. As the results, the chemical and physical characteristics of the samples approached to those of blanks. 2) Evaluation of the influence of ammonia on the alteration of the cementitious material Alteration of characteristics of cementitious material in nitrate and ammonia solution was evaluated by the water permeation test using 1mol/liter-sodium-nitrate and 0.5mol/liter-ammonia solution (denoted as NH-solution in the following). The calcium concentration of NH-solution permeated sample was higher than that of blank and the value of the calcium concentration was almost the same as that of the sodium nitrate solution case. The alteration range by the calcium leaching of the solid phase of the NH-solution case shows similar trend to that of the sodium nitrate solution case. The acceleration of the calcium dissolution was considered from this result. And the change of the water-permeability indicated the same trend with sodium-nitrate-solution case. From these results we confirmed that ammonia solution would not influence the alteration of cementitious solution.
; *; Owada, Hitoshi*; *; *
JNC TJ6400 2003-001, 44 Pages, 2003/02
JNC-TJ6400-2003-001.pdf:3.09MB
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; *; Owada, Hitoshi*; *; *
JNC TJ6420 2002-007, 28 Pages, 2002/03
JNC-TJ6420-2002-007.pdf:0.38MB
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*; Owada, Hitoshi*; Fujita, Hideki*; *
JNC TJ8400 2002-033, 60 Pages, 2002/02
JNC-TJ8400-2002-033.pdf:1.97MB
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. Since the temperature of the deep-underground is higher than that of the near surface and a part of the TRU waste generates the heat accompanied with the decay of the radioactive nuclides, the influences of the heat to the barrier material also should be taken into account. In this study, we estimated the influence of sodium nitrate and also that of the leachate from the ROBE-waste (borate-solidified body of concentrated low-level liquid waste) to the degradation of the cementitious material. We also obtained the mineralogical data of cementitious mineral after alteration in elevated temperature conditions. Results in this year are described below. (1)Alteration of characteristics of cementitious material in nitrate solution were evaluated by the water permeation test using sodium nitrate solution. The enhancement of the alteration of cementitious material due to sodium nitrate was observed. The dissolution quantity of the calcium of sodium nitrate solution permeated sample was larger than that of deionized water permeated sample (denoted as "blank" in following). Hydraulic conductivity of sodium nitrate solution permeated sample was lower than blank, but after changing permeation liquid from sodium nitrate solution to deionized water, hydraulic conductivity rose quickly. The increase of porosity and the decrease of compressive strength were observed in the case of sodium nitrate solution compared with blank. In the nitrate solution, sulfate type and carbonate type of AFm changed into the nitrate type AFm. The nitrate type AFm altered to the carbonate type AFm when the nitrate concentration was lowered. (2)The influence of the leachate from the two types of ROBE-waste on the dissolution of the cementitious material was evaluated by the leaching experiments. Dissolution of the calcium from the ...
*; Owada, Hitoshi*; Fujita, Hideki*; *; *; Yokozeki, Kosuke*; *
JNC TJ8400 2002-029, 79 Pages, 2002/02
JNC-TJ8400-2002-029.pdf:1.58MB
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or leaching as the fundamental data for the evaluation in "Study on the system development for evaluating long-term alteration of hydraulic field in Near Field" that had been carried out separately. The results in this year are shown below. (1)Hardened cement paste specimens with W/C=85% and 105% were altered and characterized after permeation. Permeability of altered part was increased, as permeated water increased. Porosity was increased at the upper part of altered specimens, and compressive strength that means the properties from altered part of specimens were decreased after water-permeation. Adequate correlations are estimated between compressive strength and porosity, permeability, Vickers hardness. From the chemical properties, it is presumed these physical changes were caused by dissolution of portlandite. (2)Hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated. As a result, after 12 weeks, porosity was increasing and Vickers hardness was decreasing at the altered area. And the water permeability and the compressive strength at the deteriorated area were simulated from relations between water permeability, compressive strength, porosity, Vickers hardness and leaching ratio of calcium. These results suggest that two methods (permeation and leaching) make up for fault of each other. It is necessary to prepare additional data, to clarify the relations between each alteration factor.
*; Owada, Hitoshi*; Fujita, Hideki*; *; *; Yokozeki, Kosuke*; *
JNC TJ8400 2002-028, 218 Pages, 2002/02
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or leaching as the fundamental data for the evaluation in "Study on the system development for evaluating long-term alteration of hydraulic field in Near Field" that had been carried out separately. The results in this year are shown below. (1)Hardened cement paste specimens with W/C=85% and 105% were altered and characterized after permeation. Permeability of altered part was increased, as permeated water increased. Porosity was increased at the upper part of altered specimens, and compressive strength that means the properties from altered part of specimens were decreased after water-permeation. Adequate correlations are estimated between compressive strength and porosity, permeability, Vickers hardness. From the chemical properties, it is presumed these physical changes were caused by dissolution of portlandite. (2)Hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated. As a result, after 12 weeks, porosity was increasing and Vickers hardness was decreasing at the altered area. And the water permeability and the compressive strength at the deteriorated area were simulated from relations between water permeability, compressive strength, porosity, Vickers hardness and leaching ratio of calcium. These results suggest that two methods (permeation and leaching) make up for fault of each other. It is necessary to prepare additional data, to clarify the relations between each alteration factor.
*; Owada, Hitoshi*; Fujita, Hideki*; *
JNC TJ8400 2002-020, 146 Pages, 2002/02
JNC-TJ8400-2002-020.pdf:4.21MB
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. Since the temperature of the deep-underground is higher than that of the near surface and a part of the TRU waste generates the heat accompanied with the decay of the radioactive nuclides, the influences of the heat to the barrier material also should be taken into account. In this study, we estimated the influence of sodium nitrate and also that of the leachate from the ROBE-waste (borate-solidified body of concentrated low-level liquid waste) to the degradation of the cementitious material. We also obtained the mineralogical data of cementitious mineral after alteration in elevated temperature conditions. Results in this year are described below. (1) Alteration of characteristics of cementitious material in nitrate solution were evaluated by the water permeation test using sodium nitrate solution. The enhancement of the alteration of cementitious material due to sodium nitrate was observed. The dissolution quantity of the calcium of sodium nitrate solution permeated sample was larger than that of deionized water permeated sample (denoted as "blank" in following). Hydraulic conductivity of sodium nitrate solution permeated sample was lower than blank, but after changing permeation liquid from sodium nitrate solution to deionized water, hydraulic conductivity rose quickly. The increase of porosity and the decrease of compressive strength were observed in the case of sodium nitrate solution compared with blank. In the nitrate solution, sulfate type and carbonate type of AFm changed into the nitrate type AFm. The nitrate type AFm altered to the carbonate type AFm when the nitrate concentration was lowered. (2) The influence of the leachate from the two types of ROBE-waste on the dissolution of the cementitious material was evaluated by the leaching experiments. Dissolution of the calcium ...
; *; Owada, Hitoshi*; *; *
JNC TJ6430 2002-002, 38 Pages, 2002/02
JNC-TJ6430-2002-002.pdf:2.33MB
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