Performance Overview of the Production Superconducting RF Cavities for the Spallation Neutron Source Linac

As part of its efforts for the SNS construction project, Jefferson Lab has produced 23 cryomodules for the superconducting linac. These modules contained 81 industrially produced multicell Nb accelerating cavities. Each of these cavities was individually tested before assembly into a cryomodule to verify that they achieved the required performance. This ensemble of cavities represents the 3rd largest set of production superconducting cavities fabricated and tested to date. The timely qualification testing of such a collection of cavities offers both challenges and opportunities. Their performance can be characterized by achieved gradient at the required Qo, achieved peak surface field, onset of field emission, and observations of multipacting. Possible correlations between cavity performance and process parameters, only really meaningful in the framework of a large scale production effort, will also be presented. In light of the potential adoption of these cavities for projects such as the Rare Isotope Accelerator or Fermilab Proton Driver, such an analysis is crucial to their success.