NEW TUNE JUMPS SCHEME IN THE LOW ENERGY PART OF THE AGS CYCLE

Abstract

During the early part of the acceleration of polarized protons, due to strong optical deformations of the lattice, the tune cannot be placed in the spin gap and the first two vertical intrinsic resonances are crossed. Recent multiparticle trackings using the Zgoubi code show that the spin resonances around G = 5 could cause as much as 5% loss of polarization. The slow acceleration rate, the two vertical and two horizontal intrinsic spin resonances can contribute to the depolarization in the region. While in the current scheme only the two horizontal intrinsic resonances are jumped, it was proposed to use the tune jump system to also accelerate the crossing of the two weak vertical intrinsic resonances and improve the polarization transmission through this region. We will show the design of this new tune jumps scheme and the expected polarization gains expected from multiparticle Zgoubi simulations. We also compare experimental measurements of the polarization transmission to the Zgoubi simulations.