COSY Slow Orbit Feedback System

The Cooler Synchrotron (COSY) at Forschungszentrum Jülich is currently carrying out the preparation for a direct measurement of the electric Dipole Moment (EDM) of the deuteron using an RF Wien filter*,**. In a magnetic storage ring with the spin vector aligned along the direction of motion, the EDM manifests in a buildup of the vertical spin component. Besides this signal, radial magnetic fields due to a distortion of the vertical closed orbit can produce a similar signal. This signal is a systematic limit of the proposed measurement procedure. Based on simulation studies***, a vertical closed orbit distortion with a RMS smaller than 0.1 mm is required to achieve a sensitivity of 10⁻¹⁹ e.cm or better. In order to accomplish this challenging goal, a slow orbit feedback system was proposed and recently commissioned at COSY. The design and commissioning results will be presented, and the future plan will also be discussed.
Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark