DESIGN OF A PROTON SUPERCONDUCTING LINAC FOR A NEUTRON SPALLATION SOURCE

We describe the design of a pulsed superconducting linac that accelerates a 2-mA average current beam of H ions from 0.2 to 1 GeV. This design would replace the normalconducting linac design of the pulsed, 6% duty factor US Spallation Neutron Source (SNS) with superconducting cavities above an energy of about 200 MeV. The design takes advantage of the large velocity acceptance of the superconducting cavities to cover the velocity range from about 200 MeV to 1 GeV with only two elliptical cavity shapes. Comparing this design with the baseline 805-MHz normal-conducting design, the superconducting design saves 33 out of 60 2.5-MW klystrons, reduces the overall length of 465 m by 100 m, and reduces the ac power by about 10 MW. We describe the design procedures including the choices of the basic parameters, design of the cavity shapes, and beam dynamics and mechanical analyses.