CAVITY QUALIFICATION AND PRODUCTION UPDATE FOR SNS-PPU CRYOMODULES AT JEFFERSON LAB

The Proton Power Upgrade (PPU) project at Oak Ridge National Lab's Spallation Neutron Source (SNS) currently being constructed will double the proton beam power capability from 1.4 to 2.8 MW by adding seven cryomodules, each containing four six-cell high-beta (β= 0.81) superconducting radio frequency cavities. Research Instruments, located in Germany, built and processed the cavities at the vendor site, including electropolishing as the final active chemistry step. Twenty-eight cavities for seven cryomodules and an additional four cavities for a spare cryomodule were delivered to Jefferson Lab and the first qualification tests were completed on all cavities as received from the vendor. The performance largely exceeded the requirements on quality factor and accelerating gradient. Six cryomodules have been assembled into strings with three cryomodules shipped and high power rf tested successfully at SNS to date.