Research On The High Precision Fiducialization Of The Magnetic Center Of An Undulator

The alignment method of Shanghai Synchrotron Radiation Facility(SSRF)undulators is used to transfer the geometry center of the magnetic component mounting surfaces to the target on the base frame of an undulator.Free electron laser(FEL)device has a relatively small good field region,so the requirement for the undulators'alignment will be high,a new calibration method for undulator magnetic fiducialization is needed.In this paper,we design and manufacture a so-called“Magnetic Landmark”and use it to achieve high precision undulator magnetic fiducialization to research this method.The introduction chapter firstly introduces the function and status of undulator in synchrotron radiation light source and free electron laser device.and the requirements for the calibration of the magnetic center of the undulator as well.And we also give the design object of an magnetic landmark.We compare two different magnetic landmarks and choose one to conduct a study.The second chapter mainly introduces the design principle of the magnetic landmark,including magnetic structure design and mechanical design.In the third chapter,we briefly introduce the measuring instrument and the calibration process of magnetic landmark in detail.The relative position relation between the targets and two quadrupole field B_y zero points is obtained.In the fourth chapter,the calibration and testing process of the undulator magnetic center is introduced in detail,and the test results are analyzed.In the end of this paper,the fifth chapter summarizes the research results of this topic and puts forward the deficiencies and the direction of future work.The measurement accuracy of the horizontal direction is 35?m and 29?m in the vertical direction.This reaches the design object of the magnetic landmark which provides a reference for the undulator alignment of the FEL device in the future.