Physical Review Special Topics. Accelerators and Beams (Feb 2010)
High precision beam momentum determination in a synchrotron using a spin-resonance method
Abstract
In order to measure the mass of the η meson with high accuracy using the dp→^{3}Heη reaction, the momentum of the circulating deuteron beam in the Cooler Synchrotron COSY of the Forschungszentrum Jülich has to be determined with unprecedented precision. This has been achieved by studying the spin dynamics of the polarized deuteron beam. By depolarizing the beam through the use of an artificially induced spin resonance, it was possible to evaluate its momentum p with a precision of Δp/p<10^{-4} for a momentum of roughly 3 GeV/c. Different possible sources of error in the application of the spin-resonance method are discussed in detail and its possible use during a standard experiment is considered.