ITER ECRH upper launcher torus diamond window; Prototyping, testing and qualification

ITER用EC上部ポートランチャーのトーラスダイヤモンド窓の試作、試験および性能評価

Schrech, S.*; Aiello, G.*; Meier, A.*; Strauss, D.*; 池田 亮介; 小田 靖久; 坂本 慶司; 高橋 幸司; Scherer, T.*

Schrech, S.*; Aiello, G.*; Meier, A.*; Strauss, D.*; Ikeda, Ryosuke; Oda, Yasuhisa; Sakamoto, Keishi; Takahashi, Koji; Scherer, T.*

The diamond window assembly is part of the ITER primary vacuum boundary and acts as the first tritium barrier and therefore it is classified as Safety/Protection Important Component. It consists of an ultra-low loss CVD diamond disk mounted in a system of metallic parts and has to fulfil adequate transmission capability for high power mm-waves. High power RF experiments with a 1st prototype had shown parasitic heating due to small gaps in the housing. 2nd prototype is equipped with inserted waveguide structures, which cover gaps in the metallic structure of the window housing. From high power RF-measurements with a 0.86 MW/100 s pulse a loss tangent of 7.110 could be estimated, corresponding to an increase of temperature of only 120 mK between inlet and outlet of the cooling system. A new prototype will be built, which is designed to fit to the single HELICOFLEX sealed waveguide structures of the ex-vessel mm-system of the EC Upper Launcher.