RECENT RHIC-MOTIVATED POLARIZED PROTON DEVELOPMENTS IN THE BROOKHAVEN AGS

The RHIC polarized proton physics program requires high luminosity and high polarization, which depend directly on the intensity, emittances and polarization delivered to RHIC by the injector chain. In the AGS, two partial snakes create gaps in the realized spin tune around the integers which allow an accelerating beam with sufficiently small vertical emittance and near-integer vertical tune to avoid the vertical imperfection and intrinsic resonances. The same strategy strengthens the many (82) weak horizontal intrinsic resonances crossed during AGS acceleration. A system speeding up these resonance crossings is the AGS JumpQuad system, consisting of 82 small (0.04) fast (100 μs) betatron tune shifts that has been commissioned and evolved during RHIC Runs 09, 10, and 11. Subtle properties of the AGS geometry and lattice, magnified into relevance by the high vertical tune can result in polarizationdamaging emittance growth when combined with the Jump Quad gymnastics. Orbit stability is critical. Some aspects of the JumpQuad system, of this commissioning effort and related developments will be described.