Development of new S-band RF window for S-band RF system of Pohang Light Source-II linear accelerator

The RF windows have been used in the Pohang Accelerator Laboratory, Pohang Light Source-II (PLS-II) must meet the conditions for operating at a peak power of 80 MW and a repetition rate of 10 Hz. In these operational conditions of the PLS-II, the original RF window that was designed for a peak power of 60 MW is more likely to inflict damages that cause vacuum leaks. Therefore, for the new RF window, the circular cavity of TE₀₁₂ mode with two coupling irises design is employed to reduce the peak electric field on the ceramic surface, while the circular cavity of TE₁₁₁ mode is used for the original RF window. The finite-difference time-domain (FDTD) simulation was used for the design. For this paper, we present the result of the prototype and its high power test.