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.

A New optical fiber system with hybrid functions of power delivery and real-time remote observation for YAG laser welding

Oka, Kiyoshi

Reza Kenkyu, 31(9), p.612 - 617, 2003/09

https://doi.org/10.2184/lsj.31.612

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.

High efficiency second-harmonic generation in multi-pass quadrature arrangement

Kiriyama, Hiromitsu; Nakano, Fumihiko*; Yamakawa, Koichi

JAERI-Research 2001-030, 26 Pages, 2001/05

JAERI-Research-2001-030.pdf:1.14MB

no abstracts in English

Very high electron temperature diagnostics using combined ruby and YAG laser Thomson scattering systems in JT-60U

Hatae, Takaki; Naito, Osamu

Proceedings of 10th International Symposium on Laser-Aided Plasma Diagnostics, p.160 - 166, 2001/00

In recent strong electron heating experiments in JT-60U, it seems that central rises above 15 keV which is measured by Ruby laser and YAG laser Thomson scattering systems. However, error bars are relatively large and it is difficult to measure the very high beyond 15 keV with high accuracy because the electron temperature region exceeds that of the original design. To improve the measurement performance in very high , we have tried the combination of existing Ruby laser system and YAG laser system. From simulations, it was found that (1) changing the form of the spectrum with the other laser is an effective way for very high measurement, (2) furthermore the combined system in YAG laser scattering is well optimized at 20keV and relative error is reduced significantly compared with original system.

Incoherent Thomson scattering diagnostics on JT-60U and JFT-2M

Hatae, Takaki; Yoshida, Hidetoshi; Yamauchi, Toshihiko; Naito, Osamu

Purazuma, Kaku Yugo Gakkai-Shi, 76(9), p.868 - 873, 2000/09

https://ci.nii.ac.jp/naid/110003825511

no abstracts in English

Development of pipe welding, cutting & inspection tools for the ITER blanket

Oka, Kiyoshi; *; *; *; Takahashi, Hiroyuki*; Tada, Eisuke

JAERI-Tech 99-048, 222 Pages, 1999/07

JAERI-Tech-99-048.pdf:24.01MB

no abstracts in English