Materials selection for ferromagnetic compensation in accelerator magnets

The magnetic hysteresis loops of Fe, Ni, and Ni-Cu in several geometrical forms were measured at 4.2 K. These materials were then evaluated for possible use as ferromagnetic correction elements in magnets wound from superconductive strands. The influences of demagnetization and cold work on the shape of the hysteresis loop were considered, and the saturation magnetizations, as well as the approach to saturation, were measured. Finally, several schemes were developed which would allow the selected alloys to be used for ferromagnetic compensation.<>