Abstract for the 15^th Joint Workshop on Electron Cyclotron Emission and Electron Resonance Heating EC-15 Yosemite National Park

Design Aspects and RF characterization of ITER-RF-CVD-Diamond-Windows

T. A. Scherer, R. Heidinger, A. Meier

Institut für Materialforschung IMF-I, Association EURATOM-FZK ,Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany

K. Sakamoto, K. Takahashi

Plasma Heating Technology Group, Japan Atomic Energy Agency (JAEA)

801-1 Mukoyama, Naka, Ibaraki 311-0193 JAPAN

M. Henderson, R. Chavan

CRPP-EPFL, Association EURATOM – Conféderation Suisse, CH-1015 Lausanne/ Switzerland

Ultra low mm-wave loss CVD diamond window assemblies with loss tangent tan d < 2 x 10^-5 have been manufactured by special brazing technique. The status of the window design is reviewed. In a new R&D phase the fabrication of the prototypical window unit will be qualified for the selected diamond grades. Diamond disks from two different companies will be compared with respect to the applicability. A characterisation will be carried out by low power measurement (FZK). The high power RF performance will be quantified by measurements (IR imaging during high power microwave loading) up to 1 MW at the 170 GHz gyrotron of JAEA and by investigating arcing processes. For this purpose special modified window assemblies (steel/copper/diamond) with waveguides are to be used.