Optimization of rotating coil system for magnetic center measurement and its application in high energy photon source

The Chinese high energy photon source is the fourth-generation light source that is currently under construction, with the booster being a significant component that has been completed by October 2022. In order to meet this timeline, 218 magnets requiring calibration were fitted with a rotating coil system and a three-coordinate measuring machine to optimize magnet center calibration. The rotating coil system is specially designed for magnetic center measurements. It employs a single-turn coil instead of the traditional complex compensated coil and uses a three-coordinate measuring machine imaging probe for precise positioning of the wire in space. This system has high accuracy, high speed, and high reliability. However, it is limited by the size of the three-coordinate measuring machine, meaning that larger magnets cannot be measured, thus limiting scalability. In September 2022, all of the magnets had been calibrated. This paper introduces the various aspects of coil design and examines the efficacy of employing three-coordinate measuring machine imaging for coil rotation center positioning and sag measurement, and provides a statistical analysis of calibration performance alongside mechanical calibration errors, the deviation between the magnet center and the mechanical center, and also a scatter analysis. Additionally, this paper also outlines the changes in the measuring time for each magnet, providing a reference for future magnet center calibration tasks.