Magnetic block measurement for insertion devices in the PAL

Abstract

Insertion devices (IDs) for the Pohang Light Source (PLS) have been developed and installed into the storage ring to produce higher photon energies. The IDs were fabricated using many Nd-Fe-B permanent magnetic blocks as the source of the magnetic field. The magnetic field characteristics of the IDs heavily depend on the directional uniformity of the magnetization of block sets. This paper describes the Helmholtz coil system (HCS) for measuring the magnetic moments of the blocks, the sorting procedures for the blocks, and the results of block measurements for the U6 undulator.