TRACKING STUDIES OF SPIN COHERENCE IN COSY IN VIEW OF EDM POLARIZATION MEASUREMENTS

Measurements of the polarization of protons and deuterons in COSY have been analyzed to prepare for similar measurements for the Electric Dipole Moment (EDM) experiment being proposed at Brookhaven • Spin tracking studies are presented, in particular the study of spin coherence time for polarization survival and possible methods to increase it A.U.Luccio et al. PST2009, September 11, 2009 1 Strategy of measurements and of simulation • In a vertical magnetic field, an injected longitudinally polarized proton, or deuteron, beam will show in time the appearance of a vertical polarization due to the EDM. The accuracy of polarization measurement (Onderwater talk, this conference) is σs ∝ 1/(PE √ NTA) with P , polarization, E electric field in particle rest frame, N , number of particles, T time of measurement, A analyzing power of polarimeter • We want to make these quantities as large of possible, and in particular we need to keep coherence of spin oscillationis for a long time • Polarimetry studies in preparation for the EDM are performed on the low energy polarized proton and deuteron storage ring COSY at Julich • Here we present simulation by spin tracking on a realistic model of the accelerator, to understand what are the limits of spin polarization survival in COSY and what are the causes and cures of spin decoherence • Following a proposal by Y. Orlov, one of us (F.Lin) has already addressed this latter issue in a preliminary study