A Study On Compact RF Pulse Compressor

RF Pulse Compressor is a passive RF structure that can compress the long RF pulse into a short pulse.More importantly,the RF power can be multiplied by several times during the compressing.Given to the low cost and high efficiency,RF Pulse Compressor is wildly focused and applied on high power RF facilities especially on Free Electron Laser(FEL)and Linear Collider facilities.Because of the high cost of FEL and Colliders,people are seeking for the best performance of light and colliding within limited construction scale,which leads the FEL and Colliders to a way of more compact and higher efficient.The Shanghai Soft X-ray Free Electron Laser(SXFEL)facility is built in the Shanghai Synchrotron Radiation Facility(SSRF)campus.Constrained by the dimensions of the campus,the electrons have to be accelerated to 840 MeV in less than 300 m,which brings forward a high request to the accelerating gradient.Nowadays,the RF source technology cannot meet the request of high gradient accelerating.Therefore,the Pulse Compressors are needed to improve the input power of accelerators.This thesis expounds the design and research work of a C-band Spherical Pulse Compressor in detail.The investigation and survey to several pulse compression schemes were presented first.The Spherical Pulse Compressor was chosen for SXFEL depending on the analysis to these different pulse compression schemes.Then the spherical resonant cavity and the operating parameters of pulse compression were introduced before the design.Based on the theory,the RF design of C-band Spherical Pulse Compressor was made using 3D electromagnetic simulation software.The prototype was machined by high precision machining technology and then measured to check the RF performance.The results of Cold Test and High Power Test were also descripted as the pulse compressor was going to be installed on high power RF facilities.This thesis also introduced a New X-band Spherical Pulse Compressor for Compact Linear Collider(CLIC)besides of the C-band Spherical Pulse Compressor for SXFEL.This new pulse compressor utilized a spherical resonant cavity as well.But the Degenerated "Whispering Gallery" Mode in BOC was used to storage the energy,which dispersed the field distribution in the mode launcher,resulting in a lower probability of RF breakdown.Several pulse compressors designed for SXFEL like Xband Spherical Pulse Compressor,X-band SLED and S-band SLED were also introduced in this thesis.Apart from these pulse compressors,this thesis also presented some new designs of RF structures like variable power splitter and phase shifter.These new designs utilized the polarizer,which reduced the size of these structures,enriched the variety and extended the application scenarios.