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Journal Articles

Stabilization of a high-order harmonic generation seeded extreme ultraviolet free electron laser by time-synchronization control with electro-optic sampling

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:4 Percentile:29.28(Optics)

no abstracts in English

Journal Articles

Full-coherent free electron laser seeded by 13th- and 15th-order harmonics of near-infrared femtosecond laser pulses

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:21.46(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$$^{2}$$ 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.

Journal Articles

Full-coherent HHG-seeded EUV-FEL locked by EOS timing feedback

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

Journal Articles

High intense full-coherent radiation of free electron laser seeded by high-order harmonics in extreme-ultraviolet region

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.

Journal Articles

The First electron bunch measurement by means of dast organic EO crystals

Okayasu, Yuichi*; Tomizawa, Hiromitsu*; Matsubara, Shinichi*; Sato, Takahiro*; Ogawa, Kanade*; Togashi, Tadashi*; Takahashi, Eiji*; Minamide, Hiroaki*; Matsukawa, Ken*; Aoyama, Makoto; et al.

Proceedings of 1st International Beam Instrumentation Conference (IBIC 2012) (Internet), 5 Pages, 2012/10

no abstracts in English

Journal Articles

Photoionization of atoms and molecules by intense EUV-FEL pulses and FEL seeded by high-order harmonic of ultrashort laser pulses

Iwasaki, Atsushi*; Sato, Takahiro*; Owada, Shigeki*; Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Kannari, Fumihiko*; Yagishita, Akira*; et al.

Reza Kenkyu, 40(9), p.687 - 690, 2012/09

no abstracts in English

Journal Articles

Synchronization of FEL and high-order harmonics of ultrashort-pulsed laser for generating intense full-coherent EUV light pulses

Iwasaki, Atsushi*; Sato, Takahiro*; Owada, Shigeki*; Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Matsubara, Shinichi*; Okayasu, Yuichi*; et al.

Proceedings of International Conference on Ultrafast Phenomena 2012 (UP 2012) (Internet), 3 Pages, 2012/07

 Times Cited Count:0 Percentile:0.03

no abstracts in English

Journal Articles

Extreme ultraviolet free electron laser seeded by high-order harmonic

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.

Journal Articles

Seeding of extreme ultraviolet free electron laser with high-order harmonic

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.

Journal Articles

EUV-FEL seeded by high-order harmonic

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.

Journal Articles

Extreme ultraviolet free electron laser seeded with high-order harmonic of Ti:sapphore laser

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:88 Percentile:96.89(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.

JAEA Reports

Corrosion Behavior of the Cladding Tube(AISI-316SS) for FBR in High Temperature Sodium

Yuhara, Shinichi*; Kano, Shigeki; Owada, Tetsuro*; Atsumo, Hideo

PNC TN951 76-07, 76 Pages, 1976/07

PNC-TN951-76-07.pdf:4.45MB

JAEA Reports

Self-welding behavior of various materials in a sodium environment; (IV) Development of self-welding equipment and its preliminary test

Mizobuchi, Shotaro*; Kano, Shigeki; Nakayama, Koichi; Namekawa, Masaru; Owada, Tetsuro*; Atsumo, Hideo

PNC TN941 75-13, 103 Pages, 1974/12

PNC-TN941-75-13.pdf:6.23MB

We developed and installed the self-welding equipment (SW-2) in self-welding Wearing Test Loop at the end of March, 1974, while had installed the wearing equipment at the end of March, 1972 and have continued to test in sodium and argon since then. SW-2 has the functions to simulate to the sliding and contact modes of LMFBR's components closelier than conventional equipments in foreign countries. The characteristics of SW-2 are as follow: (1)To be able to compress and self-weld materials in high temperature sodium and then to estimated self-weldability with the results of in-sodium tensile or in-sodium torsion tests of self-welded materials. (2)All of torsional, tensile and compressive loads can be gained by oil pressure units, and then the operation and structure of equipment became simple. (3)To be easily able to test in other environments (ex. in inert gas) by rolling the equipment of 180 degrees. (4)To be able to test under the normal load from less than 100kg to 4,000kg. Also, we conducted a part of the function test in high temperature argon and ascertained the performance of equipment to be satisfactory.

JAEA Reports

Self-welding behavior of various materials in a sodium environment (II); Weldability of hard alloy and carbide

Mizobuchi, Shotaro*; Kano, Shigeki; Namekawa, Masaru; Owada, Tetsuro*; Atsumo, Hideo

PNC TN941 74-18, 41 Pages, 1974/03

PNC-TN941-74-18.pdf:3.06MB

In this Experiment, We conducted Self-Welding Test about the Refractory Metal such as Tungsten, Molybdenum and Hard Metal (ex. Chrome-Carbide, Stellite No.6), Nickel, Niehrome. The Following Results were obtained. (1)Chrome-Carbide (coated with Detonation Gun) was effective as an Anti-Welding Material, but the Carbide with the content of Tungsten showed a strong Tendency to Self-Welding. (2)Tungsten and Molybdenum (coated with Wire Explosion Gun) were effective as Anti-Welding Materials. (3)Stellite No.6 combinated with Austenitic Stainless Steel (SUS316) showed a Tendency to Self-Welding. (4)Nickel and Nichrome were completely Self-Welded by the Formation of Diffusion Zone.

JAEA Reports

Wear tests of materials for FBR in sodium environment(II); Friction and wear of hard metals and carbides

Kano, Shigeki; *; Namekawa, Masaru; Owada, Tetsuro*; Atsumo, Hideo

PNC TN941 74-12, 57 Pages, 1974/03

PNC-TN941-74-12.pdf:1.68MB

In views of the limitation of use and the durability, it is necessary to use friction and wear resistant materials for sliding components of sodium cooled reactor. Therefore, it is required that we obtain friction and wear data about these materials in high temperature sodium. We tested about various combinations of Stellite No.6, Colmonoy No.6, Metco 16C, Deloro Stellite SF-60M, SUS304, LC-1C, LW-1N-40 and LW-5. The tests yielded the following results: (1)A certain material combination was different in behavior between friction and wear. (2)The combination of Derolo Stellite SF-60M vs. Colmonoy No.6 showed the lowest kinetic friction coefficient and specific wear rate of all combinations tested. (3)The combination of LC-1C vs. LC-1C showed the lowest static friction coefficient of all combinations tested. (4)The combination of LW-1N-40 vs. LW-1N-40 was unstable in behavior. (5)SUS 304 had the strongest self-weldability of all materials tested. (6)LW-5 was buckled during the test.

JAEA Reports

Self-Weding behavior of various materials in a sodium environment; Self-welding of SUS316 and hard chrome plating

*; Kano, Shigeki; Namekawa, Masaru; Owada, Tetsuro*; Atsumo, Hideo

PNC TN941 73-32, 38 Pages, 1973/08

PNC-TN941-73-32.pdf:6.98MB

Self-Welding occurs at the contact surface point of two materials in high-temperature sodium. In this experiment We conducted as to self-welding tendencies of the candidate materials for the fuel-assembly pad in high temperature Sodium. The results obtained are as follows: (1)Austenitic stainless steel (SUS316) showed a marked tendency to self-weld at 600$$^{circ}$$C, and some different material couples with SUS420 and Cr$$_{3}$$C$$_{2}$$ (coated with plasma-spray) were self-welded by the formation of diffusion layer. (2)Hard chrome plating material couples with austenitic stainless steel showed tendency to self-welding, but the same material couples showed little welding. (3)Numerous crackings were showed on surface layer of the hard chrome plating after sodium immersion test. (4)Molybdinum and Hard alloy materials showed no-self welding.

JAEA Reports

Corrosion behavior of the cladding tube (AISI Type-316SS) for FBR in high temperature sodium; Experimental studies on the oxygen concentration dependence of the corrosion in sodium

*; Kano, Shigeki; Owada, Tetsuro*; Atsumo, Hideo

PNC TN941 73-24, 64 Pages, 1973/07

PNC-TN941-73-24.pdf:4.71MB

Some experiments in order to investigate the oxygen concentration dependence of the corrosion in sodium were carried out on the domestic cladding tube (nominal dimension of 6.3 mm outside diameter at 0.35 mm wall thickness) of Type-316 stainless steel. The daughter loops, M-2 and M-11, were used for mass-transfer test of the tube specimen, in which the test condition was individually selected on the oxygen concentration; the cold trap temperature was controlled to keep its concentration at 200$$^{circ}$$C in M-2 and 150$$^{circ}$$C in M-11. Mass-transfer test was made up to about 2000 hours in flowing sodium and the maximum temperature of test sections was held at 650$$^{circ}$$C. After exposure in sodium, the following analyses were made on the specimens: weighing, surface roughness, SEM, X ray, X ray microscan, mechanical properties and others. The results obtained after exposure at 650$$^{circ}$$C are summarlized as follows: (1)General corrosion rate of the cladding tube speoimen is remarkably dependent on the oxygen concentration. It shows distinguished increase as the cold-trap temperature increases. (2)The leaching layer of iron was observed, in which alloying elements were depleted in nickel and chromium. Elemental leaching and depletion in the surface layer was mainly observed inwards along the grain boundary in the neighbour of the surface exposed in sodium. Thickness of the leaching layer was about 30 $$mu$$m. (3)At the surface layer of the specimens exposed in sodium, the presence of ferrite was confirmed by X ray, and the surface roughness of the specimens after exposure in the higher oxygen concentration increased to about 1.8 times as large as those before exposure.

JAEA Reports

Wear tests of materials for FBR in sodium environment(I); Wear of hard metals

Kano, Shigeki; Mizobuchi, Shotaro*; Namekawa, Masaru; *; Atsumo, Hideo; Owada, Tetsuro*

PNC TN941 73-17, 99 Pages, 1973/06

PNC-TN941-73-17.pdf:3.57MB

In views of the limitation of use and the durability, it is necessary to use wear resistant materials for sliding components of sodium cooled reactors. Therefore, it is required that we obtain wear data about these materials in high temperature sodium. We conducted wear tests about various pairs of hard metals (stellite No.1, stellite No.6, colmonoy No.5 and colmonoy No.6). The tests yielded the following results: (1)The specific wear rate was less and the friction coefficient was lower and more stable in the test about a pair of hard metals (Colmonoy No.5 & No.6) than about both pairs of SUS304 coupled with stellite No.1 and Colmonoy No.6. (2)The friction coefficient was lower in the test about the pair of SUS304 coupled with stellite No.1 than coupled with colmonoy No.6. (3)The friction-affected Layer was found on the sliding surface. (4)The appearance of the sliding surface was considerably different between in sodium and in argon.

Oral presentation

Temporal overlapping for an HH seeded EUV-FEL operation by using EO-based timing-drift controlling system

Matsubara, Shinichi*; Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; et al.

no journal, , 

no abstracts in English

Oral presentation

Stable operation of HHG-seeded EUV-FEL at the SCSS test accelerator

Tomizawa, Hiromitsu*; Hara, Toru*; Ishikawa, Tetsuya*; Ogawa, Kanade*; Tanaka, Hitoshi*; Tanaka, Takatsugu*; Togashi, Tadashi*; Togawa, Kazuaki*; Yabashi, Makina*; Aoyama, Makoto; et al.

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)