OPERATIONAL EXPERIENCE WITH A NEAR-INTEGER WORKING

During the RHIC polarized proton run in FY 2006 it became evident that the luminosity performance is limited by the beam-beam effect. With a working point between 2/3 and 7/10, and the necessity to mirror the tunes of the two RHIC rings at the diagonal, the beam with a horizontal tune closest to 2/3 showed poor lifetime. To overcome this limitation, a near-integer working point has been proposed. Tracking studies performed at both working points showed a larger dynamic aperture near the integer tune than above 2/3. In Run-8, this new working point was commissioned in one ring of RHIC, while the other ring was operated at the same working point as in Run-6. In this paper we report the commissioning process and operational experience with this new working point.