Progress of the high current Prototype Accelerator for IFMIF/EVEDA

Okumura, Yoshikazu; Ayala, J.-M.*; Bolzon, B.*; Cara, P.*; Chauvin, N.*; Chel, S.*; Gex, D.*; Gobin, R.*; Harrault, F.*; Heidinger, R.*; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.203 - 205, 2015/09

http://www.pasj.jp/web_publish/pasj2015/proceedings/PDF/FROL/FROL08.pdf

Under the framework of Broader Approach (BA) agreement between Japan and Euratom, IFMIF/EVEDA project was launched in 2007 to validate the key technologies to realize IFMIF. The most crucial technology to realize IFMIF is two set of linear accelerator each producing 125mA/CW deuterium ion beams up to 40MeV. The prototype accelerator, whose target is 125mA/CW deuterium ion beam acceleration up to 9MeV, is being developed in International Fusion Research Energy Center (IFERC) in Rokkasho, Japan. The injector developed in CEA Saclay was delivered in Rokkasho in 2014, and is under commissioning. Up to now, 100keV/120mA/CW hydrogen ion beams and 100keV/90mA/CW duty deuterium ion beams are successfully produced with a low beam emittance of 0.21 .mm.mrad (rms, normalized). Delivery of RFQ components will start in 2015, followed by the installation of RF power supplies in 2015.

Experimental verification of velocity bunching via shot-by-shot measurement at S-band photoinjector and linac

Iijima, Hokuto; Uesaka, Mitsuru*; Sakamoto, Fumito*; Ueda, Toru*; Kumagai, Noritaka*; Serafini, L.*

Japanese Journal of Applied Physics, Part 1, 44(7A), p.5249 - 5253, 2005/01

https://doi.org/10.1143/JJAP.44.5249

We represent an experimental verification of a bunch compression method named "velocity bunching". The velocity bunching based on the rectilinear compression uses a traveling wave accelerating tube as a compressor. The experiment was performed by an S-band photoinjector and a linac at Nuclear Engineering Research Laboratory, University of Tokyo. The shot-by-shot bunch length was measured to be 0.5 0.1 ps (rms) in average by the femtosecond streak camera for a bunch charge of 1 nC. The experimental result is in good agreement with PARMELA simulations.

Study of ultra-high gradient wakefield excitation by intense ultrashort laser pulses in plasma

Kotaki, Hideyuki

JAERI-Research 2002-031, 88 Pages, 2002/12

JAERI-Research-2002-031.pdf:3.33MB

We investigate a nonlinear phenomena in laser-plasma interaction, a wakefield excited by intense laser pulses, and a possibility of generating an electron beam by an intense laser pulse. Ionization of gas with a self-focusing causes a broad continuous spectrum with blueshift. The normal blueshift depends on the laser intensity and the plasma density. We have found the spectrum shifts to fixed wavelength independent of the laser power and gas pressure. We call the phenomenon "anomalous blueshift". An intense laser pulse excites a wakefield in plasma. The wakefield excited by 2TW, 50fs laser pulses in a gas-jet plasma is measured with a time-resolved frequency domain interferometer (FDI). This is the first time-resolved measurement of the wakefield of 20GeV/m in a gas-jet plasma. The FDI and the anomalous blueshift will be modified to an optical injection system as an electron beam injector. In a simulation we obtain a high quality intense electron beam. The result illuminates the possibility of a high energy and a high quality electron beam acceleration.

Gas and pellet injection systems for JT-60 and JT-60U

Kizu, Kaname; Hiratsuka, Hajime; Miyo, Yasuhiko; Ichige, Hisashi; Sasajima, Tadayuki; Nishiyama, Tomokazu; Masaki, Kei; Honda, Masao; Miya, Naoyuki; Hosogane, Nobuyuki

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.396 - 409, 2002/09

https://doi.org/10.13182/FST02-A236

Designs and operations of the gas system and pellet injection systems for JT-60 were described. A gas injection valve that is a key component of the gas injection system was developed using a multi layer piezoelectric element. The maximum flow rate of this system is 43.3 Pam3/s. The valve has mechanism for adjustment at atmospheric side meaning that a repair and an adjustment can be conducted without ventilation inside a vacuum vessel. Two systems of pellet injector; one is pneumatic drive and another is centrifugal one were developed. The pneumatic type attained a pellet velocity of 2.3 km/s, which was the world record at the time in 1988. On the other hand, the centrifugal one was developed in 1998. This injector can eject trains of up to 40 cubic (2.1 mm)3 pellets at frequencies of 1~10 Hz and speed of 0.1~1.0 km/s. A guide tube for a magnetic high field side top injection HFS(top)) was also developed in 1999. The pellet injection experiment with the HFS system started in 2000. In addition, another guide tube for HFS(mid) injection was newly developed and installed in March 2001.

Bright electron multi-bunch production for the high power JAERI-FEL oscillator

Nishimori, Nobuyuki; Hajima, Ryoichi; Nagai, Ryoji; Shizuma, Toshiyuki; Sawamura, Masaru; Kikuzawa, Nobuhiro; Minehara, Eisuke

Proceedings of 13th Symposium on Accelerator Science and Technology, p.458 - 460, 2001/00

Stable and bright electron multi-bunches at 16.5 MeV with a long macro-pulse duration over 0.4 ms, which consists of 4,000 micro-bunches, have been produced at the Japan Atomic Energy Research Institute (JAERI) superconducting linac driven Free-Electron Laser (FEL) facility. The bunch charge is 0.5 nC with peak current higher than 100 A. The bright electron bunch was generated using a RF compression made in two stages in the injector system, and directly led to a quasi-CW kilowatt lasing. In this paper, we describe the bunching system and electron beam performances in JAERI-FEL.

Beamlet interaction in multi-aperture negative ion source

Fujiwara, Yukio; Hanada, Masaya; Kawai, Kenichi*; *; Miyamoto, Kenji; Okumura, Yoshikazu; Watanabe, Kazuhiro

JAERI-Research 99-013, 32 Pages, 1999/02

JAERI-Research-99-013.pdf:1.51MB

no abstracts in English

Radiation induced conductivity and voltage holding characterisics of insulation gas for the ITER-NBI

Fujiwara, Yukio; Hanada, Masaya; Inoue, Takashi; Miyamoto, Kenji; Miyamoto, Naoki*; Ohara, Yoshihiro; Okumura, Yoshikazu; Watanabe, Kazuhiro

Proc. of Joint Meeting of 8th Int. Symp. on the Production and Neutralization of Negative Ions & Beams, p.205 - 215, 1997/00

no abstracts in English

Development of a 500 keV, 22A D ion source for the neutral beam injector for JT-60U

Okumura, Yoshikazu; Fujiwara, Yukio; Honda, Atsushi; Inoue, Takashi; Kuriyama, Masaaki; Miyamoto, Kenji; Miyamoto, Naoki*; Mogaki, Kazuhiko; Nagase, Akihito*; Ohara, Yoshihiro; et al.

Review of Scientific Instruments, 67(3), p.1018 - 1020, 1996/03

https://doi.org/10.1063/1.1146743

no abstracts in English

Merging beam experiment of intense negative ions for advanced compact neutral beam injectors

Inoue, Takashi; Miyamoto, Kenji; Mizuno, Makoto; Okumura, Yoshikazu; Ohara, Yoshihiro; G.D.Ackerman*; C.F.Chan*; W.S.Cooper*; J.W.Kwan*; M.C.Vella*

15th IEEE/NPSS Symp. on Fusion Engineering,Vol. 1, 0, p.474 - 477, 1994/00

no abstracts in English

Negative ion based neutral beam injector for JT-60U

Okumura, Yoshikazu; Araki, Masanori; Hanada, Masaya; Inoue, Takashi; Kunieda, Shunsuke; Kuriyama, Masaaki; Matsuoka, Mamoru; Mizuno, Makoto; Ohara, Yoshihiro; Tanaka, Masanobu*; et al.

Production and Neutralization of Negative Ions and Beams; AIP Conference Proceedings 287, p.839 - 848, 1994/00

https://doi.org/10.1063/1.44830

no abstracts in English