Applications of stimulated brillouin scattering phase conjugate mirror to Thomson scattering diagnostics in JT-60U and ITER

Hatae, Takaki; Naito, Osamu; Kitamura, Shigeru; Sakuma, Takeshi*; Hamano, Takashi*; Nakatsuka, Masahiro*; Yoshida, Hidetsugu*

Journal of the Korean Physical Society, 49, p.S160 - S164, 2006/12

no abstracts in English

Acceleration of high current fully stripped carbon ion beam by direct injection scheme

Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro; Okamura, Masahiro*; Jameson, R. A.*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Sakakibara, Kazuhiko*; Takano, Jumpei*; Yamamoto, Kazuo*; Iwata, Yoshiyuki*; et al.

Review of Scientific Instruments, 77(3), p.03B305_1 - 03B305_4, 2006/03

https://doi.org/10.1063/1.2172358

Acceleration of a 17mA 100keV/u C ion beam has been successfully achieved with an RFQ linac by means of "Direct injection scheme". The Direct injection scheme is a new scheme for injecting an ion beam from a laser ion source to the RFQ linac without a low energy beam transport line to avoid a beam loss due to the space charge effect. The high current C beam is required for single turn injection to a synchrotron to reduce the size of synchrotron magnets. The high current C beam produced by an ion source with a Nd-YAG laser was injected to the RFQ linac by the Direct injection scheme. It has been proved experimentally that the fully-stripped carbon ion beam with a current more than 10mA can be accelerated by the RFQ linac.

0.5-kHz, 5-W optical parametric oscillator pumped by the second harmonic of a Nd:YAG laser

Maruyama, Yoichiro

Optical Engineering, 44(9), p.094202_1 - 094202_3, 2005/09

https://doi.org/10.1117/1.2044507

A high average power BBO optical parametric oscillator pumped by a Nd:YAG laser second harmonic is demonstrated at the pulse repetition frequency of 0.5 kHz. Average power of 5.4 W (10.8 mJ) with the energy conversion efficiency of 45% is obtained for Type-I BBO OPO. The output power still increasing and undesirarble thermal effects are not observed.

Acceleration of high current and highly charged carbon beam using direct injection scheme

Kashiwagi, Hirotsugu; Okamura, Masahiro*; Jameson, R. A.*; Hattori, Toshiyuki*; Hayashizaki, Noriyosu*; Sakakibara, Kazuhiko*; Takano, Jumpei*; Yamamoto, Kazuo*; Iwata, Yoshiyuki*; Fujimoto, Tetsuya*

Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.182 - 184, 2005/07

The carbon beam from a Nd-YAG laser ion source was accelerated successfully by an RFQ linac using Direct injection scheme. The "Direct injection scheme" is the way to inject an ion beam to the RFQ linac without a low energy beam transport line to avoid space charge effect due to a high intensity beam from the laser ion source. About 30mA of a carbon beam was detected by a faraday cup just behind the RFQ linac.

Improvement of Thomson scattering diagnostics using stimulated-Brillouin-scattering-based phase conjugate mirrors

Hatae, Takaki; Nakatsuka, Masahiro*; Yoshida, Hidetsugu*

Purazuma, Kaku Yugo Gakkai-Shi, 80(10), p.870 - 882, 2004/10

http://ci.nii.ac.jp/naid/110003827868

A high performance phase conjugate mirror by stimulated Brillouin scattering (SBS-PCM) is applied to Thomson scattering diagnostics in JT-60U for the first time. To improve the measurement performance, two developments were performed with SBS-PCM. First, we developed a new optical design to provide a double-pass scattering scheme with SBS-PCM. A laser beam passing through the plasma is reflected by the SBS-PCM, and a reflected beam returned back through the same path as coming one by the phase conjugate effect, and passed through the plasma again. The double path Thomson scattering scheme demonstrated in JT-60U plasma that a factor of 1.6 increase of the scattered light in contrast with single-pass scattering. Second, an improvement of the output power of YAG laser system using the SBS-PCM was performed. As a result, average power was increased over 8 times in contrast with conventional system, and was achieved up to 368 W (7.4 J 50 Hz). A multi-pass Thomson scattering scheme is also proposed based on the results of double-pass scattering.

High power pulsed green lasers

Kiriyama, Hiromitsu

Recent Research Developments in Optics, Vol.3, p.155 - 171, 2003/12

no abstracts in English

Development of high power pulsed green lasers

Kiriyama, Hiromitsu; Yamakawa, Koichi

Reza Gakkai Dai-313-Kai Kenkyukai Hokoku; Kokino Kotai Reza To Sono Oyo, p.1 - 6, 2003/09

no abstracts in English

Conceptual design of cesium removal device for ITER NBI maintenance

Oka, Kiyoshi; Shibanuma, Kiyoshi

JAERI-Tech 2003-004, 57 Pages, 2003/03

JAERI-Tech-2003-004.pdf:2.36MB

Cesium is required in order to generate a stable negative ion of hydrogen in an ion source of the neutral beam injector (NBI), which is one of the plasma-heating devices for International Thermonuclear Experimental Reactor (ITER). After long time operation of NBI, the cesium deposits to the insulators supporting the electrode. Due to the deterioration of the insulation resistance, the continuous operation of the NBI will be difficult. In addition, the NBI device is activated by neutron from D-T plasma, so that a periodic removal and cleaning of the cesium on the insulators by remote handling is required. A study of the cesium removal scenario and device is therefore required considering remote handling. In this report, a cesium removal procedure and conceptual design of the cesium removal device using laser ablation technique are studied, and the feasibility of laser ablation is shown.

Development of laser cutting/welding system for remote maintenance of ITER manifold

Yamaoka, Hiroto*; Tsuchiya, Kazuyuki*; Awano, Toshihiko*; Oka, Kiyoshi

Ishikawajima Harima Giho, 42(5), p.260 - 264, 2002/09

http://ci.nii.ac.jp/naid/40005409717

no abstracts in English

A High repetition rate, single-frequency Nd:YAG laser oscillator and its characteristics

Maruyama, Yoichiro; Oba, Masaki; Kato, Masaaki

JAERI-Tech 2002-004, 13 Pages, 2002/02

JAERI-Tech-2002-004.pdf:3.65MB

For the in-situ measurement of various substances in the atmosphere by using DIAL (Differential Absorption LIDAR) , a high repetition rate tunable laser is required to obtain data within a few seconds. As the pump source of the tunable laser, the performance of high repetition rate and high average power is indispensable. For the generation of high quality laser radiation, a laser oscillator with 1 kHz pulse repetition rate is made and seeded with very narrow linewidth single-longitudinal mode laser radiation from the outside of the oscillator cavity and its characteristics are studied. As the results, after the thermal equilibrium of the oscillator laser crystal, a single-longitudinal and near TEMoo transverse mode are realized at the pulse repetition rate between 0.5kHz and 1kHz. Single frequency operation is preserved by controlling the cavity length. The average output power of 3W (3mJ per pulse) is obtained. It is confirmed that this oscillator has enough performance as a oscillator of MOPA (Master Oscillator Power amplifier) system.