Calculation of higher order nonradiative spin resonance strengths in circular accelerators

A new program eilms is used to calculate the strengths of first and higher order nonradiative spin resonance strengths in a storage ring, including full strength Siberian Snakes. A perturbative formalism is employed, in powers of the orbital oscillation amplitudes. Simulation results are presented for RHIC (Relativistic Heavy Ion Collider). Some of the subtleties in the application of these ideas to rings with Snakes are described. Calculations are also performed and compared with some recent experimental measurements of higher order spin resonance strengths at COSY (Cooler Synchrotron). It is well known that in some cases higher order spin resonances can be stronger than lower order ones; this fact is explained.