SSRF波荡器EPU148动力学积分场效应磁场垫补  

Field shimming for effect of EPU148 dynamic field integral at SSRF

作　　者：张淼[1,2] 周巧根[1] 

机构地区：[1]中国科学院上海应用物理研究所嘉定园区,上海201800 [2]中国科学院大学,北京100049

出　　处：《核技术》2016年第7期15-20,共6页Nuclear Techniques

基　　金：国家自然科学基金(No.11175238)资助~~

摘　　要：阐述了减少"APPLE(Advanced Planar Polarized Light Emitter)-II"型可变椭圆极化波荡器动力学积分场效应的"L-Shimming"垫补方法的原理。优化设计了上海光源"梦之线"光束线站波荡器EPU148磁场垫补方案,磁场实际测量结果和模拟计算结果基本一致,误差小于最大垫补量的10%,垫补后动力学积分场效应对束流的影响减少一个数量级。机器研究结果显示,波荡器EPU148所有工作磁气隙和所有工作相位下引起的工作点漂移小于0.001,对束流注入效率基本没有影响,证明了其动力学积分场效应垫补是成功的。Background： The dynamic field integral means the integrated magnetic field along the electron＇s trajectory in undulator, which will cause the tune shift, dynamic aperture reduction and beam lifetime shortening, etc. The effect is inversely proportional to the square of the electron energy and the filed transverse roll-off. The field of the APPLE-II type Elliptical Polarization Undulator （EPU） has a very fast, intrinsic, transverse roll-off, especially for the vertical polarization mode, creating significant dynamic field integral effect to the beam motion. The research on the dynamic field integral effect of APPLE-II type EPU and the corresponding magnetic field shimming method is the hotspot in the field of international particle accelerator. Purpose： The principle of ＂L-Shimming＂ method to reduce dynamic field integral effect for APPLE-II type EPU is stated in this paper. Methods： The optimization design of ＂L-Shimming＂ for EPU148 dynamic field integral effect has been done with ＂RADIA Code＂. Results： The measurement results of flipping coil indicate that the magnetic field strength measured is coincident with the simulation result, and the error is less than 10% of the maximum shimming quantity. After shimming, the dynamic field integral effect of EPU148 will reduce an order of magnitude. The machine study has been done after EPU148 is installed in SSRF storage ring with the tune shift less than 0.001, and the beam injection efficiency has almost not been influenced with EPU148 in all operation polarization modes and all operation gaps. Conclusion： It is proved that the shimming to reduce EPU148 dynamic field integral effect is successful.

关 键 词：磁场垫补 动力学积分场 波荡器 

分 类 号：TL594[核科学技术—核技术及应用]