Spin Flipping through an Intrinsic Depolarizing Resonance by Strengthening It

Abstract

We recently accelerated a polarized proton beam from 95 to 380 MeV through both the $G\ensuremath{\gamma}=2$ imperfection depolarizing resonance and the $G\ensuremath{\gamma}=7\ensuremath{-}{\ensuremath{\nu}}_{y}$ intrinsic depolarizing resonance. The imperfection resonance flipped the spin, while the intrinsic resonance initially caused partial depolarization. We then pulsed a vertical kicker magnet for about 500 ns to increase the beam's vertical betatron amplitude; this made the intrinsic resonance much stronger. By varying the strength and start time of the kicker, we observed a sharp spin flip due to the now very strong intrinsic depolarizing resonance.