Intrinsic resonances and AC-dipole simulations of 3He in the AGS Booster

Polarized He collisions are part of future RHIC physics programs and of the eRHIC project. The anomalous magnetic moment of He (G=-4.184) is roughly three times greater than that of protons (G=1.793), a polarized species that is already used at the Collider-Accelerator complex at BNL. Because of the higher anomolous magnetic moment and possibly injecting into the AGS at rigidities beyond 7 T · m, He may have to cross depolarizing intrinsic resonances while accelerating in the Booster. To overcome these strong intrinsic resonances we look to an AC-dipole, which will need to be installed in the Booster. An AC-dipole is a magnet that induces large betatron oscillations which forces the entire bunch to experience a stronger resonance and induce a spin flip of all particles. An artificial intrinsic resonance is created, with close proximity to the original intrinsic resonance, which requires simulations to gauge what magnet strength is required. Simulations have been performed using zgoubi regarding the resonances 0 + νy, 12− νy, and 6 + νy and show that the AC-dipole is effective at overcoming these resonances. Benefits of avoiding the 0 + νy and crossing the 12− νy and 6 + νy in the Booster presents the advantage of allowing injection above the 0 + νy in the AGS and minimizes the orbit distortions from the snakes.