Unexpectedly wide rf-induced synchrotron sideband depolarizing resonances

Abstract

Using an rf solenoid magnet, we studied the depolarization of a stored 104.1 MeV vertically polarized proton beam. The two primary rf depolarizing resonances were properly centered around the protons’ circulation frequency fc, at fc(3−νs) and fc(νs−1), where νs is the spin tune; moreover, each resonance was roughly consistent with the expected width of about 720 Hz. Each primary rf resonance had two synchrotron sideband resonances at the expected frequencies. The two νs−1 sidebands were deep dips while the two 3−νs sidebands were very shallow; this was not expected. Moreover, all four sideband resonances were unexpectedly wider than the two primary resonances.Received 11 May 1998DOI:https://doi.org/10.1103/PhysRevE.58.4973©1998 American Physical Society