混合型波荡器的3维优化

Optimized design considerations for hybrid undulator

以波荡器辐射波和共振电子能及混合型波荡器的解析计算为基础,通过3维磁场的有限元计算,在欧洲光源横向优化基础上,给出了同步辐射和自由电子激光用混合型波荡器纵向优化参数,进而给出了用于DUVFEL混合型波荡器的设计计算参数。加侧位和顶部永磁块后,峰值磁场分别提高到0.722T和0 773T,辅助以1μm量级分辨率的磁间隙调节机械系统,磁场分辨率好于10-4T量级。

The hybrid undulator is optimized in beam direction based on transverse optimization developed in ESRF. The thickness of the magnet and the pole is optimized at the ratio of 16:9 for the maximized peak field. The analytical equations for designing the hybrid undulator are listed and discussed. One prototype hybrid undulator with 25 mm period length is being constructed with NdFeB magnets and vanadium permendur poles by the optimized results. The magnet gap of the hybrid undulator can be tunable in 10-300 mm. At 10 mm magnetic gap, the undulator peak field can reach 0.648 T with only the main magnet. It can be enhanced to 0.722 T and 0.773 T by further adding the side magnet and top magnet. The field resolution is better than 10-4 T with 1 μm gap tuning system driven by servomotor. All optimization are based on 3-dimensional finite element electromagnetic computation, the Opera3d. The typical technical parameters of the hybrid undulator are listed. The computed induction field in the beam axis and in the middle plane of the hybrid undulator is respectively shown, which illustrates that the optimized configuration has more than 10 mm good field region. The field distribution in the pole surface shows that it already reaches saturation with the present NdFeB magnets and vanadium permendur pole technology.