Wiggler as spin rotators for RHIC

The spin of a polarized particle in a circular accelerator can be rotated with an arrangement of dipoles with field mutually perpendicular and perpendicular to the orbit. To achieve spin rotation, a given field integral value is required. The device must be designed in a way that the particle orbit is distorted as little as possible. It is shown that wigglers with many periods are suitable to achieve spin rotation with minimum orbit distortions. Wigglers are also more compact than more established structures and will use less electric power. Additional advantages include their use for nondestructive beam diagnostics. Results are given for the Relativistic Heavy Ion Collider (RHIC) in the polarized proton mode