First Test of a Partial Siberian Snake During Polarized Beam Acceleration

Abstract

We recently studied the first acceleration of a spin-polarized beam through a depolarizing resonance using a partial Siberian snake. We accelerated polarized protons from 95 to 140 MeV while ramping a 10% partial Siberian snake along with the acceleration cycle. The 10% partial snake suppressed all observable depolarization due to the $G\ensuremath{\gamma}=2$ imperfection depolarizing resonance which occurred near 108 MeV during acceleration. However, 20% and 30% partial Siberian snakes apparently moved the $G\ensuremath{\gamma}=7\ensuremath{-}{\ensuremath{\nu}}_{y}$ intrinsic depolarizing resonance from near 177 MeV into our energy range; this caused some interesting but not-yet-fully understood depolarization.