Abstract
Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternative Gradient Synchrotron(AGS). The relatively weak but numerous horizontal resonances are the main source of polarization loss in the AGS. A pair of horizontal tune jump quads have been used to overcome these weak resonances. The locations of the two quads have to be chosen such that the disturbance to the beam optics is minimum. The emittance growth has to be mitigated for this method to work. In addition, this technique needs very accurate jump timing. Using two partial Siberian snakes, with vertical tune inside the spin tune gap and 80% polarization at AGS injection, polarized proton beam had reached [Formula: see text] proton per bunch with 65% polarization. With the tune jump timing optimized and emittance preserved, more than 70% polarization with 2[Formula: see text] protons per bunch has been achieved.
Highlights
Polarized proton beams encounter many depolarizing resonances during acceleration in synchrotrons
The intrinsic resonance is only associated with the vertical betatron tune νy for vertical polarization, as the vertical spin can only be
These horizontal intrinsic resonances can be divided into two categories: one with M + νx; one with K − νx
Summary
Polarized proton beams encounter many depolarizing resonances during acceleration in synchrotrons. A dual partial snake scheme[5] has been used in the AGS to overcome both imperfection and vertical intrinsic resonances. The intrinsic resonance is only associated with the vertical betatron tune νy for vertical polarization, as the vertical spin can only be. This is an Open Access article published by World Scientific Publishing Company. In the presence of a partial snake, the stable spin direction is not purely vertical.
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