Large diamond disks for ECRH microwave windows in nuclear fusion

Nuclear fusion devices feature electron cyclotron resonance heating systems for plasma heating and stabilization, with diamond windows acting as vacuum and safety confinement barriers. Diamond is the only option for longpulse operation in the MW-range applications, given its exceptional combination of optical, thermal and mechanical properties. Dielectric measurements have qualified almost one hundred disks of artificial diamond for their integration into metallic structures to form the complete windows. Optical and mechanical investigations of the disks, together with dedicated numerical analyses of the windows, complete the characterization of these essential components in nuclear fusion.