一种波荡器段间四极铁远程精密调节机构的研制

摘要

自由电子激光(Free Electron Laser,FEL)装置是一种以相对论高品质电子束作为工作介质,在周期磁场中以受激发射方式放大电磁辐射的新型激光源.FEL装置中的四极铁中心相对于束流中心线的高精度就位与否将直接影响束流的品质,上海软X射线自由电子激光装置和大连极紫外相干光源装置的波荡器段间四极铁均采用基于束流准直方法(Beam based alignment,BBA),需要可远程精密调节四极铁位置的机构.BBA四极铁远程精密调节机构主要由可远程精密定位的电移机构和控制系统构成.电移机构采用精密滚珠丝杠驱动的滑块组合机构,可实现垂直于束流的水平和竖直高度方向的二维调节.本文简单描述了BBA四极铁远程精密调节机构的机械设计,对BBA四极铁远程精密调节机构的测试方法及结果进行了详细分析.该系统集成测试结果表明,机构运动过程中采用光栅尺进行反馈,其定位精度和重复性均达到了设计指标要求.%Background:The high position accuracy of the key parts such as the quadrupole magnet relative to the beam center is very important for the Free Electron Laser (FEL) equipment, and will directly affect the quality of the beam.Purpose:This study aims to realize the precise beam-based aligment of the quadrupole by mechanical design of a remote-controlled quadrupole mover.Methods:Beam based alignment (BBA) technique was applied to adjusting the center position of quadrupole with a remote-controlled high accuracy mover and its control system. Experimental tests and analysis for the quadrupole mover by the different feedback control were carried out for the undulator segments of the soft X-ray FEL (SXFEL) in Shanghai and the Dalian Coherent Light Source (DCLS) project in China. Results:The positioning accuracy and repeatability error of the quadrupole mover is less than 3μm by the grating ruler feedback control, but it is more than 3μm by the rotary encoder feedback control.Conclusion:The mechanical design and experimental tests of the quadrupole mover are accomplished. The positioning accuracy and repeatability of the quadrupole mover meet the design indices by the grating ruler feedback control.