P1–14: Thermal crack of a RF output window for an S-band 50 kW average power klystron

The failure mechanism of an S-band high power RF window was studied experimentally and computationally in this paper. Destructive cracking failures were observed for some times near the window under 50 kW average power. Samples of the cracked ceramic disk were assayed; the result of which suggested that the thin, carbon film, deposited to the inner surface in the course of the hot test, occurred to be responsible for window output power level. This result can be explained by the simulation with HFSS and ANSYS code.