Concepts for the design of magnets at target locations subjected to very high radiation levels

Magnets for advanced hadron facility secondary beam lines will be positioned close to targets at which nuclear radiation levels will be about 10⁸ rad/h. Designs are proposed in which the magnet coils are remote from the beam apertures and shielded from radiation by the poles or other nonmagnetic material. The magnet yokes and poles are integrated into the radiation shielding surrounding the targets. If necessary, the coils can be removed for servicing without exposing the parts of the magnet with very high residual radiation fields. In this proposed design it will be unnecessary to have vacuum joints adjacent to the magnets, because the parts of the magnet close to the beam tube should never need to be removed for maintenance.