Design of Double Barrier Ceramic Radio Frequency Vacuum Window

Vacuum windows are an essential part of any radio frequency (RF) system which launches/couples RF power from an atmospheric to a vacuum environment. This paper describes the RF design of a double barrier ceramic coaxial vacuum window. Alumina 99.5% pure is considered as ceramic barrier material while inner and outer conductors are oxygen-free copper. As the initial design approach the thickness, slope, depth of ceramic in the conductor is varied and the performance of the window is studied. The design is optimised to achieve the best insertion loss, return loss response for operating frequency range up to 65MHz.

White beam diagnostics using X-ray back-scattering from a CVD diamond vacuum window

Collecting back-scattered X-rays from vacuum windows using a pinhole X-ray camera provides an efficient and reliable method of measuring the beam shape and position of the white synchrotron beam. In this paper, measurements are presented that were conducted at ESRF beamline ID6 which uses an in-vacuum cryogenically cooled permanent-magnet undulator (CPMU18) and a traditional U32 undulator as its radiation sources, allowing tests to be performed at very high power density levels that were adjusted by changing the gap of the undulators. These measurements show that it is possible to record beam shape and beam position using a simple geometry without having to place any further items in the beam path. With this simple test setup it was possible to record the beam position with a root-mean-square noise figure of 150 nm.