Proposal of partial Siberian snake based on helical magnets for AGS

A scheme of partial Siberian snake is considered for polarized proton acceleration at AGS. The snake consists of four identical helical magnets with the field amplitude about 4.0 T on axis and provides proton spin rotation by about 32 degrees per one pass at the injection energy 2.5 GeV. Orbit distortions do not exceed 2 cm inside the insertion. The influences of the snake fields' nonlinearities on the beam dynamics are discussed.