Towards Fracture Toughness Measurements of MPA CVD Diamond in Nuclear Fusion Devices

Optical quality polycrystalline diamond is the only window material allowing transmission of high-power microwave beams in nuclear fusion devices. Failure to fracture is the main failure mode for diamond, which is integrated in the shape of disks in the so-called window units. This paper reports on the path to measure the fracture toughness of this diamond for a later potential structural integrity assessment of the disks based on fracture mechanics.