A Summary and Status of the SNS Ring Vacuum Systems

The Spallation Neutron Source (SNS) ring is designed to accumulate high intensity protons. Ultrahigh vacuum of 10-9 Torr is required in the accumulator ring to minimize beam-residual gas ionization. To reduce the secondary electron yield (SEY) and the associated electron cloud instability, the ring vacuum chambers are coated with titanium nitride (TiN). This paper describes the design, fabrication, assembly and vacuum processing of the ring and beam transport line vacuum chambers as well as the associated instrumentation