POLARIZATION REVERSAL OF STORED PROTON-BEAMS IN THE INDIANA COOLER

A spin flipper of reliable and robust long-term operation was develope d and has been used successfully at the Indiana University Cooler Stor age Ring. To reverse the polarization of the stored beam, the frequenc y of a rf solenoid is swept adiabatically across a depolarizing resona nce frequency. Depolarizing sidebands to the resonance are eliminated by shorting out the ring's bunching rf cavity prior to the frequency s weep. With the spin flipper it is no longer necessary to dump the stor ed beam and to refill the ring with protons of opposite spin state. Ra ther, beam accumulation continues without reversing the spin at inject ion, and instead the polarization of the stored beam is flipped period ically. Thus the luminosity is significantly increased when the flippe r is used. (C) 1996 American Institute of Physics.