Toward polarized antiprotons: Machine development for spin-filtering experiments

The paper describes the commissioning of the experimental equipment and the machine studies required for the first spin-filtering experiment with protons at a beam kinetic energy of 49.3MeV in COSY. The implementation of a low-β insertion made it possible to achieve beam lifetimes of τb=8000s in the presence of a dense polarized hydrogen storage-cell target of areal density dt=(5.5±0.2)×1013atoms/cm2. The developed techniques can be directly applied to antiproton machines and allow for the determination of the spin-dependent p¯p cross sections via spin filtering.