OVERCOMING INTRINSIC SPIN RESONANCES WITH AN RF DIPOLE

A coherent spin resonance excited by an rf dipole was used to overcome depolarization due to intrinsic spin resonances at the Alternating Gr adient Synchrotron (AGS) at Brookhaven National Laboratory. We found t hat our data are consistent with a full spin flip of a polarized proto n beam, without emittance growth, at G gamma = 12 + nu(z) and 36 - nu( z), by adiabatically exciting a vertical coherent betatron oscillation using a single rf dipole magnet. The interference pattern observed be tween the intrinsic spin resonance and the coherent spin resonance agr ees well with multiparticle spin simulations based on a simple two-res onance model. The interference pattern can be used for beam diagnostic s.