BackgroundThe main body of the high energy photon source (HEPS) storage ring contains 288 pre-collimating units. Due to the smaller size of the magnets in the cells, the positioning accuracy of magnets is required to be 3~5 times higher than that in previous projects.PurposeThis study aims to improve the accuracy of magnet pre-collimation and explore the high measurement accuracy and positioning accuracy of the unit magnet in the pre-collimation experiment.MethodsThe influence of multi-path laser layout schemes on the accuracy of magnetic pre-collimation was firstly simulated by combining the multichannel laser interferometry system with the magnet pre-collimation technology. Then, the simulation software MATLAB was used to optimize the layout scheme of "three high and one low" with the minimum standard deviation of the measured target point as the objective. Finally, four Leica AT960 laser trackers were employed for experimental verification of the measurement accuracy.ResultsThe results show that the standard deviation of the measured target point is less than 10 μm in the space range of 12.1 m×5.97 m×3 m, and the measurement accuracy is significantly improved compared with that of a single laser tracker.ConclusionsThe designed project meets the experimental working conditions and design requirements, it lays a foundation for subsequent beam center calibration and magnet calibration.
