Fig. 1. Diagram of copper foil tape layout for the superconducting undulator

Fig. 2. Schematic diagram of magnetic measurement sledge structure

Fig. 3. Magnetic field distributions of the middle 120 periods measured by two Hall probes at the current of 100 A

Fig. 4. Magnetic field distribution along the magnetic neutral axis under a 100 A current

Fig. 5. Relative position between Hall probe No.1 and the magnetic neutral plane in the y-direction during the magnetic measurement process

Fig. 6. Phase error distribution of two magnetic measurements atwi the current of 100 A before optimization

Fig. 7. Phase error distribution of theoretical calculation and actual measurement wiat the current of 100 A after optimization