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Journal Articles

Development of reliable diamond window for EC launcher on fusion reactors

Takahashi, Koji; Illy, S.*; Heidinger, R.*; Kasugai, Atsushi; Minami, Ryutaro; Sakamoto, Keishi; Thumm, M.*; Imai, Tsuyoshi

Fusion Engineering and Design, 74(1-4), p.305 - 310, 2005/11

 Times Cited Count:13 Percentile:66.34(Nuclear Science & Technology)

A new diamond window with the copper-coated edge for an EC launcher is developed. The diamond window is designed to cool its disk edge. Since Cu is coated at the entire edge, ingress of cooling water into a transmission line in case of failure on the edge is negligible. In addition, corrosion of Al blaze between the edge and the Inconel cuffs can be avoided. A 170GHz, RF transmission experiment equivalent to a MW-level transmission was carried out to investigate the capability of the edge cooling. The transmission power and pulse are 55kW and 3sec, respectively. Temperature increase was 45$$^{circ}$$C and alomost became constant. Thermal calculation with tan$$delta$$ of 4.4$$times$$10$$^{-4}$$ and thermal conductivity of 1.9kW/m/K agrees with the experiment. Since tan$$delta$$ of the diamond is much higher than the actual one (tan$$delta$$=2$$times$$10$$^{-5}$$), the temperature increase corresponds to that of 1MW transmission. It concludes that the Cu coating dose not degrade the edge cooling capability and improves the reliability of the diamond window.

Journal Articles

Development of EC launcher components for ITER

Takahashi, Koji; Kobayashi, Noriyuki*; Kasugai, Atsushi; Sakamoto, Keishi

Journal of Physics; Conference Series, 25, p.75 - 83, 2005/00

Recent progress of the development on the ITER equatorial EC launcher components, such as the steering mirrors, its drive system, the waveguide components and the diamond vacuum windows, is reported. Thermmo-mechanical analysis of the recent mirror design shows that maximum temperature increase of 187$$^{circ}$$C at the reflecting surface and maximum stress of 242MPa at the inner surface of the cooling tube are obtained. In the cyclic test of the spiral tube mock-up, the cyclic number of 1.3$$times$$10$$^{6}$$ is succeeded without failure. In the window development, the fabrication of the Cu-coated edge diamond window and the high power transmission test were done. The Cu-coating on the disk edge can avoid water ingress in the launcher (vessel) under the assumption of the crack formation toward edge. Transmission experiment indicative to 1.2MW, was carried out. Temperature increase of 50$$^{circ}$$C agrees with the calculation. It concludes that the Cu-coated window is capable of MW-level transmission and improves its reliability.

Journal Articles

Application of diamond window for infrared laser diagnostics in a tokamak device

Kawano, Yasunori; Chiba, Shinichi; Inoue, Akira*

Review of Scientific Instruments, 75(1), p.279 - 280, 2004/01

 Times Cited Count:12 Percentile:54.37(Instruments & Instrumentation)

It has been successful to apply CVD diamond plate as the vacuum window for infrared CO$$_{2}$$ laser interferometry and polarimetry for electron density measurement in the JT-60U tokamak. In comparison with to use the conventional zinc-selenide windows, the Faraday rotation component at diamond windows was small as negligible. This resulted in the improvement of the Faraday rotation measurement for a tokamak plasma by polarimetry.

Journal Articles

Development of EC launcher and diamond window for ITER

Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi; Kasugai, Atsushi; Heidinger, R.*; Thumm, M.*; Moeller, C. P.*

Proceedings of IAEA TM on ECRH Physics and Technology for ITER (CD-ROM), 7 Pages, 2003/00

A front steering (FS) launcher and a remote steering (RS) one have been studied for ITER. In the analysis of a mirror(Cu alloy) for FS launcher, max. temperature of 333$$^{circ}$$C and max. induced stress of 136MPa, less than allowable stress(200MPa), were obtained at the mirror surface under 1MW/1line in CW operation. The efficient transmission ($$eta$$$$>$$95%) at -12$$^{circ}$$$$<$$$$theta$$$$<$$12$$^{circ}$$ and 170GHz was performed for both polarizations in the experiments of a square corrugated waveguide for the RS launcher. RF and pressure tests of the diamond window irradiated by neutron were carried under JA/EU(FZK) collaboration. Neutron fluence of the window was 10$$^{21}$$n/m$$^{2}$$, whereas the estimated annual fluence at the window position is 10$$^{18}$$$$sim$$10$$^{19}$$n/m$$^{2}$$. Transmission of 0.48MW-30sec and 0.2MW-132sec were performed. It was successfully demonstrated that the irradiated window withstood 0.4MPa, which was twice higher than the ITER requirement. Diamond windows are applicable for ITER.

Journal Articles

Chemical vapor deposition diamond window as vacuum and tritium confinement barrier for fusion application

Takahashi, Koji; Sakamoto, Keishi; Kasugai, Atsushi; Imai, Tsuyoshi; Brandon, J. R.*; Sussmann, R. S.*

Review of Scientific Instruments, 71(11), p.4139 - 4143, 2000/11

 Times Cited Count:14 Percentile:63.3(Instruments & Instrumentation)

no abstracts in English

JAEA Reports

High power millimeter wave transmission through CVD diamond

Kasugai, Atsushi; Sakamoto, Keishi; Takahashi, Koji; Tsuneoka, Masaki; Imai, Tsuyoshi; O.Braz*; M.Thumm*

JAERI-Research 97-020, 7 Pages, 1997/03


no abstracts in English

Journal Articles

High-power millimeter-wave transmission through CVD diamond

Braz, O.*; Thumm, M.*; Kasugai, Atsushi; Sakamoto, Keishi; Takahashi, Koji; Tsuneoka, Masaki; Imai, Tsuyoshi

22nd International Conference on Infrared and Millimeter Waves Conference Digest, p.144 - 145, 1997/00

no abstracts in English

Journal Articles

High power 170 GHz test of CVD diamond for ECH window

Braz, O.*; Kasugai, Atsushi; Sakamoto, Keishi; Takahashi, Koji; Tsuneoka, Masaki; Imai, Tsuyoshi; Thumm, M.*

International Journal of Infrared and Millimeter Waves, 18(8), p.1495 - 1503, 1997/00

 Times Cited Count:38 Percentile:86.65(Engineering, Electrical & Electronic)

no abstracts in English

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