Tunable double disk window for ECH&CD system of ASDEX-U

A double disk window was designed which fulfils the broadband transmission requirements for the torus window in a step-tunable ECH&CD system for ASDEX-U. Thermo-hydraulic as well as thermo-mechanical modelling were performed in order to analyse the cooling layout and the stress in the window under operation conditions. Specific issues of the window fabrication are presented.