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Minehara, Eisuke
Nuclear Instruments and Methods in Physics Research A, 557(1), p.16 - 22, 2006/02
Times Cited Count：11 Percentile：60.27(Instruments & Instrumentation)The JAERI FEL facility at Tokai, Ibaraki, Japan has been well known one of the two existing and operating superconducting energy recovery linacs together with one more of JLAB (Jefferson national accelerator facility) FEL facility at Newport News, Virginia, U.S.A. We have independently and successfully developed one of the most advanced and newest accelerator technologies named "superconducting energy recovery linacs (ERLs)" and the application technologies using ERLs in future. We plan to report the current high power FEL upgrade program research, stress corrosion cracking prevention technology research, large current and high brightness photoelectron gun research of negative-electron affinity (NEA) photocathode and NEA electron-excitation cathode as the most important elemental technology in realizing many powerful ERLs.
Minehara, Eisuke; Hajima, Ryoichi; Iijima, Hokuto; Kikuzawa, Nobuhiro; Nagai, Ryoji; Nishimori, Nobuyuki; Nishitani, Tomohiro; Sawamura, Masaru; Yamauchi, Toshihiko
Proceedings of 27th International Free Electron Laser Conference (FEL 2005) (CD-ROM), p.305 - 308, 2005/00
The JAERI high power ERL-FEL has been extended to the more powerful and efficient free-electron laser (FEL) than 10kW for nuclear energy industries, and other heavy industries like defense, shipbuilding, chemical industries, environmental sciences, space-debris, and power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, we need the efficient and powerful FEL driven by the JAERI compact, stand-alone and zero boil-off super-conducting RF linac with an energy-recovery geometry. Our discussions on the ERL-FEL will cover the current status of the 10kW upgrading and its applications of non-thermal peeling, cutting, and drilling to decommission the nuclear power plants, and to demonstrate successfully the proof of principle prevention of cold-worked stress-corrosion cracking failures in nuclear power reactors under routine operation using small cubic low-Carbon stainless steel samples.
Nishimori, Nobuyuki; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Sawamura, Masaru
Proceedings of 3rd Asian Particle Accelerator Conference (APAC 2004), p.625 - 627, 2004/00
no abstracts in English
Nishimori, Nobuyuki
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.108 - 110, 2003/11
The evolution of the field of an FEL oscillator at zero detuning length of an optical cavity (dL = 0) is studied analytically. The field on the leading edge at the first round trip is the same as that of a self-amplified spontaneous emission (SASE) FEL characterized by an FEL parameter. The field evolves with round trips by interaction with electrons. The field in the early stage of the evolution is found to scale with the FEL parameter and the round-trip number, and is similar to that of SASE with high electron beam density.
Nishimori, Nobuyuki; Nagai, Ryoji; Minehara, Eisuke; Kikuzawa, Nobuhiro; Hajima, Ryoichi; Sawamura, Masaru
Proceedings of 28th Linear Accelerator Meeting in Japan, p.159 - 161, 2003/00
no abstracts in English
Minehara, Eisuke
Nuclear Instruments and Methods in Physics Research A, 483(1-2), p.8 - 13, 2002/05
Times Cited Count：21 Percentile：77.35(Instruments & Instrumentation)In order to realize a tunable, highly-efficient, high average power, high peak power and ultra-short pulse free-electron laser(FEL) as a supertool [1]of the 21st for all , the JAERI FEL group and I have developed an industrial FEL driven by a compact, stand-alone and zero-boil-off super-conducting rf linac[2] with an energy-recovery geometry as a conceptual design. Our discussions on the supertool will cover market-requirements for the industrial FELs, some answers from the JAERI compact, stand-alone and zero-boil-off cryostat concept and operational experience over these 8 years, our discovery of the new, highly-efficient, high-power, and ultra-short pulse lasing mode[3], and the energy-recovery geometry.
Minehara, Eisuke
Oyo Butsuri, 71(2), p.214 - 216, 2002/02
We have developed free-electron lasers driven by a superconducting rf linac to demonstrate a powerful and efficient FEL, and the prototype of the FEL has successfully lased to get 0.1kW as the world-strongest FEL average power in February 1998. Two years after the first lasing, the second world-records of ultra-fast pulse of 250fs, efficiency of 7%, and average and peak power of 2.34kW and 1GW at 22 micron have successfully been obtained using a well-improved FEL and superconducting rf linac driver. The breakthrough of ultra-short pulse, efficiency and power in FELs has been realized using the improved driver performance of high density current and high-quality acceleration, and a discovery of sustained superradiance FEL oscillation. Resultantly, we have been successfully able to demonstrate high-efficiency larger than the theoretical limit and ultra-fast pulse of 3.4cycles, and 250fs. In the text, the novel technology of FELs driven by a superconducting rf linac will be briefly reported.
Nishimori, Nobuyuki; Hajima, Ryoichi; Nagai, Ryoji; Sawamura, Masaru; Kikuzawa, Nobuhiro; Shizuma, Toshiyuki; Minehara, Eisuke
Proceedings of 8th European Particle Accelerator Conference (EPAC 2002), p.822 - 824, 2002/00
The energy recovery linac with superconducting accelerator was constructed in JAERI (Japan Atomic Energy Research Institute) FEL, and the commissioning started in December 2001. The electron beam is injected into the energy recovery system at 2 MeV, accelerated up to 17 MeV and damped after deceleration down to 2 MeV by the same accelerator. The bunch charge of the electron beam is 0.5 nC with micro-pulse repetition rate of 10 MHz. The energy recovery rate was estimated to be more than 95 % from an RF input power with and without energy recovery. In this paper, we show the present results of energy-recovery experiments.
Minehara, Eisuke; Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Kikuzawa, Nobuhiro; Sugimoto, Masayoshi; Yamauchi, Toshihiko; Hayakawa, Takehito; Shizuma, Toshiyuki
Proceedings of 13th Symposium on Accelerator Science and Technology, p.150 - 154, 2001/10
We need a powerful and efficient free-electron laser(FEL) for industrial uses, for examples, pharmacy, medical, defense, shipbuilding, semiconductor industry, chemical industries, environmental sciences, space-debris, power beaming and so on. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, the JAERI FEL group and I have successfully demonstrated the efficient and powerful FEL driven by a compact, stand-alone and zero-boil-off super-conducting rf linac with an energy-recovery geometry. Our discussions on the FEL will cover market-requirements for the industrial FELs, some answers from the JAERI compact, stand-alone and zero-boil-off cryostat concept and operational experience over these 8 years, our discovery of the new, highly-efficient, high-power, and ultra-short pulse lasing mode, and the energy-recovery geometry.
Minehara, Eisuke
JAERI-Conf 2000-019, p.115 - 116, 2001/02
no abstracts in English
Nishimori, Nobuyuki; Nagai, Ryoji
Proceedings of 13th Symposium on Accelerator Science and Technology, p.95 - 99, 2001/00
We have observed sustained saturation in a Free-Electron Laser (FEL) oscillator at zero detuning of an optical cavity for the first time, and confirmed that the optical pulse length at zero detuning is 250 fs FWHM at wavelength of 22 um. The optical length corresponds to three optical cycles, which is the fewest cycles ever achieved at FELs in the world. The peak FEL power reaches 0.8 GW with the single optical pulse energy of 200 uJ. The sustained lasing at zero detuning is not allowed in conventional FEL oscillator theories and the physical mechanism is under investigation.
Minehara, Eisuke; Nagai, Ryoji; Sawamura, Masaru; Takao, Masaru*; *; *; Sasaki, Shigemi; Okubo, Makio; *; Suzuki, Yasuo; et al.
Nuclear Instruments and Methods in Physics Research A, 331, p.182 - 185, 1993/00
Times Cited Count：9 Percentile：66.97(Instruments & Instrumentation)no abstracts in English
