A 3＋1/2cell DC-SC photo-injector for PKU-FEL facility is under development, which is an upgrade design of the successful 1-4-1/2cell DC-SC photo-injector. The Lorentz detuning and tuning structure for the 3＋1/2cell ...A 3＋1/2cell DC-SC photo-injector for PKU-FEL facility is under development, which is an upgrade design of the successful 1-4-1/2cell DC-SC photo-injector. The Lorentz detuning and tuning structure for the 3＋1/2cell superconducting cavity is presented in this paper. The Lorentz force detuning coefficient is 1.2 Hz/（MV/m）^2 with double stiffening rings for the half cell and single stiffening rings between the adjacent TESLA cells. With the special stiffening structure, the 3＋1/2cell whole cavity needs only one tuner. The influences of the tuning on frequency shift, field flatness and average gradient are discussed in this paper. The simulation results show that the stiffening rings＇ design is successful.展开更多
Beam emittance is one of the most important parameters for electron sources. To investigate the beam emittance of the 3.5-cell DC-SC photocathode injector developed at Peking University, a multi-slit emittance measure...Beam emittance is one of the most important parameters for electron sources. To investigate the beam emittance of the 3.5-cell DC-SC photocathode injector developed at Peking University, a multi-slit emittance measurement device has been designed and manufactured. The designed slit width, mask thickness and beamlet drift length are 100 ~m, 3 mm and 430 mm respectively. It is suitable for the electron beam with energy of about 5 MeV and the average current less than 0.1 mA. The preliminary measurement result of the rms emittance of the electron beam produced by the DC-SC injector is about 5 7 mm.mrad.展开更多
基金Supported by Major State Basic Research Development Program of China(2002CB713600)
文摘A 3＋1/2cell DC-SC photo-injector for PKU-FEL facility is under development, which is an upgrade design of the successful 1-4-1/2cell DC-SC photo-injector. The Lorentz detuning and tuning structure for the 3＋1/2cell superconducting cavity is presented in this paper. The Lorentz force detuning coefficient is 1.2 Hz/（MV/m）^2 with double stiffening rings for the half cell and single stiffening rings between the adjacent TESLA cells. With the special stiffening structure, the 3＋1/2cell whole cavity needs only one tuner. The influences of the tuning on frequency shift, field flatness and average gradient are discussed in this paper. The simulation results show that the stiffening rings＇ design is successful.
基金Supported by Major State Basic Research Development Program of China (2011CB808302)Peking University grant for interdisciplinary or developing disciplinary studies
文摘Beam emittance is one of the most important parameters for electron sources. To investigate the beam emittance of the 3.5-cell DC-SC photocathode injector developed at Peking University, a multi-slit emittance measurement device has been designed and manufactured. The designed slit width, mask thickness and beamlet drift length are 100 ~m, 3 mm and 430 mm respectively. It is suitable for the electron beam with energy of about 5 MeV and the average current less than 0.1 mA. The preliminary measurement result of the rms emittance of the electron beam produced by the DC-SC injector is about 5 7 mm.mrad.
