Partial Siberian snake with a polarized beam.

Abstract

The effect of a radio frequency (rf) solenoid magnet and a partial Siberian snake on a stored 120 MeV vertically polarized proton beam was experimentally studied at the Indiana University Cooler Ring. A partial Siberian snake should be able to overcome the relatively weak imperfection depolarizing resonances in proton accelerators up to 10 GeV. The "rf-induced" depolarizing resonance frequencies were measured using several weak partial Siberian snakes. The snake's longitudinal magnetic field tilts the stable spin direction from the vertical direction and shifts the depolarizing resonances toward higher frequencies. A 4% snake shifts the resonance frequency by 11 kHz which corresponds to a spin tune shift of 0.00688. We also experimentally studied a spin-flip technique by ramping the rf solenoid frequency through a depolarizing resonance. We found about a 1.8% polarization loss per flip after many flips.