Techniques for Measurement and Correction of the SNS Accumulator Ring Optics

The Spallation Neutron Source (SNS) Accumulator Ring will reach peak intensities of 1.5×10¹⁴protons/pulse through multi-turn charge-exchange injection. Accumulation of these unprecedented beam intensities must be accomplished while maintaining extremely low losses (less than 1 W/m). It is anticipated that the understanding and control of the ring optics will be important for achieving these low loss rates. We describe our plans for measuring and correcting the optical functions of the accumulator ring lattice.

INTRODUCTION

At full design intensity, the SNS accumulator ring will reach peak intensities of protons/pulse. The 1-msec long linac beam pulse is accumulated in the ring over 1060 turns via charge-exchange multi-turn injection using a stripping foil. In order to allow hands-on maintenance of beamline components, a stringent loss criterion of less than 1 W/m has been established. It is anticipated that good understanding and control of the ring optics will be important for achieving these low loss rates.