The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the...The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the high gradient in the cryogenic photoinjector make it possible to improve the performance of new light sources.As an upgrading scheme for the Shanghai Soft X-ray Free-Electron Laser,this study explores a novel photocathode RF gun by introducing the TM_(02)mode into the cathode cell of a 2.6-cell electron gun,which improves the RF performance,particularly in terms of the monopole field.Furthermore,the optimized cathode cell with the TM_(02)mode can reduce the errors resulting from installation and decrease the dark current with alternative cathodes.In this study,the beam dynamics in a photoinjector were optimized using a 500-pC,5-ps beam,and its feasibility was examined.This paper presents the entire RF design process,including the adjustment of the RF structure,coupler design,local field,and multipole mode suppression to provide theoretical guidance for subsequent manufacturing and assembly.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12222513 and 12405178)。
文摘The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the high gradient in the cryogenic photoinjector make it possible to improve the performance of new light sources.As an upgrading scheme for the Shanghai Soft X-ray Free-Electron Laser,this study explores a novel photocathode RF gun by introducing the TM_(02)mode into the cathode cell of a 2.6-cell electron gun,which improves the RF performance,particularly in terms of the monopole field.Furthermore,the optimized cathode cell with the TM_(02)mode can reduce the errors resulting from installation and decrease the dark current with alternative cathodes.In this study,the beam dynamics in a photoinjector were optimized using a 500-pC,5-ps beam,and its feasibility was examined.This paper presents the entire RF design process,including the adjustment of the RF structure,coupler design,local field,and multipole mode suppression to provide theoretical guidance for subsequent manufacturing and assembly.
