- Open Access
Compact waveguide-type ceramic window for radio frequency cavity in synchrotron storage ring
Phys. Rev. Accel. Beams 29, 073801 – Published 10 July, 2026
DOI: https://doi.org/10.1103/8c1n-3zwl
Abstract
In this study, a waveguide-type radio frequency (rf) ceramic window with a simple structure was developed for vacuum-sealing rf cavities up to 250 kW in the synchrotron storage ring of a fourth-generation light source. The rf window was designed for easy and quick replacement in the event of ceramic failure. It was assembled with low dielectric loss tangent () alumina ceramic in a copper frame for mounting between waveguide flanges. The ceramic surface was coated with titanium nitride (TiN) to suppress multipactor discharge. However, two problems occurred during the high-power rf operation test: overheating of the ceramic due to an unexpectedly high and multipactor discharge on the ceramic surface. To eliminate high- alumina before welding the window, screening methods were developed to remove such alumina. To suppress the discharge, a magnetic field was applied to the ceramic plate, which was coated with diamondlike carbon (DLC), a material with a lower secondary electron yield (SEY) than TiN. After these countermeasures were implemented, an operation at 250 kW rf was maintained for more than a week without interruption.
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