Design and test of the motion system for HEPS storage ring horizontal collimator

Background Collimators in the storage ring of high-energy photon source(HEPS)are used to localize the beam loss,making it possible to set local radiation shields.The motion system of the collimator is used to adjust the position of the movable jaws for controlling the beam loss precisely.Moreover,dump mode of the collimator increases the risk of jaw damage from beam heat deposition.According to the requirements of motion accuracy and the severe working condition of the collimators,a new design of a two-axis motion system for the movable jaws is proposed,realizing high-precision control and extending the lifetime.Purpose The purpose of this paper is to introduce the designing scheme of the motion system for HEPS storage ring horizontal collimators,including the analyses of the key components,the structure design of the motion system and test results of the prototype.Method Temperature excursions of the movable jaw are calculated theoretically and analyzed by ANSYS,respectively.The motion accuracy of the system is measured by coordinate measuring machine.Result The temperature excursion is simulated as 1883 K while using graphite as the absorbing material at dump mode.The motion system consists of a mobile slide for aperture adjustment and a manual wedge jack for vertical adjustment.The average coupled deviation in horizontal direction of the wedge jack is 0.031 mm,while the maximum positioning deviation of the slide is 0.014 mm,both having good repeatability and being compensable.Conclusion Test results of the prototype indicate that the new design of the motion system is applicable to the horizontal collimator in HEPS storage ring.The problem of the jaw rotation in the horizontal movement is found,and the solution is given.

Design and test of the beam-based alignment sextupole experimental mover prototype for HEPS

Background Sextupoles in the storage ring of HEPS will be adjusted based on beam trajectory.The mechanical design of a beam-based alignment sextupole mover should be developed.The motion accuracy of the mover should be better than 5µm under 450 kg load of sextupoles.The movement range is required to be±0.3 mm in both horizontal direction and vertical direction.And the first-order natural frequency of the magnet support system which include movers should be higher than 54 Hz.Purpose The purpose of this paper is to design a mover prototype and to realize its movement performance and equivalent stiffness.And to find the difficulties of development of this mover.Method Interferometer is used to measure the motion accuracy,and pressure accelerometer is used to test the mover equivalent stiffness.Combining with the actual measurement results of equivalent stiffness,the natural frequency of the magnet support system is simulated.Result The motion accuracy reaches to 5.3µm in vertical direction and 1µm in horizontal direction,respectively.The equivalent stiffness of the mover prototype can just able to meet the requirement of frequency of the HEPS magnet support system.Unwanted movement coupling has occurred during the mover exercises in vertical direction.Conclusions Through the research of experimental mover prototype,the methods have been learnt to improve the movement performance and equivalent stiffness of the mover based on sliding friction under high load.However,further researches and improvements are necessary to fix the coupling error during the vertical movement.