Proton Polarization in AGS: Horizontal resonance correction and open issues

• Vincent Schoefer (Brookhaven National Laboratory)

The helical dipole partial snake magnets in the AGS cause a set of depolarizing resonances driven by the horizontal betatron motion of the beam. Starting in 2011, those resonances were crossed with a fast tune jump to mitigate polarization loss. In the last two years of polarized proton operation for the RHIC program, a system of fast ramping skew quadrupoles was commissioned in the AGS to completely correct those resonances. We will discuss the status of the skew quadrupole system commissioning, its present limitations and possible paths forward. There will be brief discussion of how those efforts might help diagnose sources of polarization loss other than these horizontal resonances.