Field profiling and magnetic axis reconstruction in solenoids using a translating induction-coil magnetometer

This paper presents a method for simultaneously measuring the axial field profile and reconstructing the magnetic axis of solenoids using a translating induction-coil magnetometer. The magnetometer consists of a 22-layer PCB sensor, which is tracked by a laser tracker to measure the magnetic flux density along the geometric axis of the magnet bore. We propose a magnetic axis reconstruction method in which the measured data are represented using a cylindrical-harmonic expansion, thereby imposing Maxwellian consistency on the reconstructed field, and compare it to a baseline polynomial approximation. Measurements performed on a prototype solenoid for the CERN AD electron-cooler upgrade confirm that the proposed harmonic method yields superior accuracy and linearity, with a magnetic-axis repeatability on the order of 100 m, establishing the translating induction-coil magnetometer as a reliable tool for magnetic measurement and magnet alignment.