Study And Design Of A Novel Kind Of Kicker For HALF

It took over decades development for synchrotron radiation(SR)source before it became an important tool in many scientific fields.Starting with the first generation of SR source,which is parasitic on the high energy collider,the SR source has developed to the fourth generation.As a special-use machine,the second generation of SR source produced the SR light mainly based on the bending magnets.To further increase the brightness of the synchrotron light,the third generation of SR source added insertion elements,such as undulator and wiggler,on the drift section of the storage ring.In recent years,a diffraction-limited storage ring(DLSR)based light source has been proposed as the fourth generation of SR source.The main design purpose of the DLSR is to reduce the beam horizontal natural emittance so that it can approach the diffraction limit of X-rays.High gradient quadrupoles and high strength sextupoles are used in DLSRs to achieve an ultralow emittance,which leads to strong nonlinear dynamic effects and a reduction in the dynamic aperture size.The local bump injection scheme became very difficult for DLSRs,therefore,it is necessary to find an alternative injection scheme for DLSRs.Hefei Advanced Light Facility(HALF)is a fourth-generation light source based on the diffraction-limited storage ring,which is proposed by the National Synchrotron Radiation Laboratory(NSRL)and located in the soft X-ray and VUV region.The pre-research of the HALF has been completely done and all the system components were accepted last year.The new lattice design of the HALF increased the beam dynamic aperture from 2 mm to 10 mm,so we can use an off-axis injection scheme with a single nonlinear kicker(NLK).In this injection scheme,the NLK is installed downstream of the septum,and it has little influence to the stored beam because the magnetic field strength and gradient at the center of the NLK is nearly zero.In this paper,we purposed and designed a novel kind of NLK which is used in the off-axis injection for HALF.The principle and layout of the single pulsed magnet injection scheme were introduced and the designed parameters of the NLK were determined according to the injected requirements of the HALF.Simulations of the magnetic field of the NLK with and without the coated ceramic chamber were carried out by using OPERA software.The structure and the dimension parameters of the NLK were determined.The prototypes of the NLK and the ceramic chamber were produced and the magnetic field measurement were carried out on the NLK prototype.The measured field were in good agreement with the simulated field,and several improvements were made to solve the problems aroused during the measurements.Simulations analysis of the s-parameters,beam wake field,longitudinal beam coupling impedance and energy loss factor of the NLK were also done by using CST software.A longitudinal beam coupling impedance measurement platform were built and the coaxial wire method were used to measure and calculate the s-parameters,the longitudinal beam coupling impedance and the loss factors of the NLK and the reference tube,and the beam loss energy were obtained finally.