Problems of the compensation methods for the spin depolarizing resonances in the strong focusing synchrotron.

摘要

The achievement of a high energy polarized proton beam requires the reduction of depolarization during acceleration. This depolarization will occur at spin resonances where the spin precession frequency equals that of a horizontal magnetic field component. There are basically two types of first order depolarizing resonances. One type is an intrinsic resonance which is excited by the periodical focusing structure of the machine. The resonance occurs at (gamma)G=nN (plus minus) (nu)(sub z), where (gamma), G, n, N and (nu)(sub z)are the Lorentz energy factor the gryomagnetic factor, and integer, the superperiodicity number of the machine and the vertical betatron tune, respectively. The resonance strength is proportional to the vertical betatron oscillation amplitude. The other type is an imperfection resonance which is due to the magnet misalignment leading to vertical closed orbit distortion (COD). This resonance occurs at (gamma)G=nN(plus minus)k, where k is the harmonic number of the vertical COD. The resonance strength is proportional to the amplitude of the vertical COD. This paper reports on phenomena and problems about depolarizing resonances encountered in accelerating polarized protons at the AGS and the KEK PS. 31 refs. (ERA citation 15:035449)