AGS polarized proton project

At the end of this year, polarized H- beam will be injected into the AGS, where it will be stripped and subsequently accelerated to 26 GeV/c. 20 keV polarized H- are produced in an ion source working at ground potential by colliding polarized H0 with cesium beams and 12 μA of H- have already been achieved in 0.5 ms pulses. 20 keV beam is transported to an RFQ linac where it is accelerated to 750 keV. 750 keV LEBT line matches the RFQ output emittance to the acceptance of the existing 200 MeV linac to reach the desired AGS injection energy. The degree of polarization will depend critically on how well we can cross some 30 depolarizing resonances in the AGS. They can be divided into two types: (1) intrinsic resonances due to natural periodicity of the AGS will be crossed in less than one revolution (approx. 2 μs) by a fast tune jump generated by 12 fast quadrupoles and their modulators, and (2) imperfection resonances due to magnet misalignment will be minimized by generating harmonic correction using 96 existing dipole magnets. In addition, all existing AGS multipoles will be programmed to tailor the tune and chromaticity during the acceleration to further facilitate resonance crossing. In order to insure rapid tune up and commissioning of polarized beams, four independent polarimeters will be used to measure polarization