The wire alignment method in a magnetic field measurement system

In the magnetic field measurement system, a single-core CuZr wire is used in both the stretched-wire (SW) and pulsed wire measurement (PWM) systems. Before measuring the magnetic field of the undulators, the CuZr wire must be aligned with the center of the undulator mechanism. The SW system is then employed to locate the magnetic field center of the undulator. The traditional method involves using a theodolite and level to align the CuZr wire with the center of the undulator mechanism. However, for cryogenic permanent magnet undulators (CPMUs), superconducting magnets, or any magnets installed in a vacuum chamber, aligning the CuZr wire with the center of the mechanism using traditional methods presents challenges. In this paper, we propose a method that utilizes the wire's contact with the magnet to observe changes in resistance for positioning purposes, thereby overcoming the limitations of center alignment in chamber-surrounded undulator mechanisms.