Vertical Test Results for the LCLS-II 1.3 GHz First Article Cavities

The LCLS-II project requires 35 1.3 GHz cryomodules to be installed in the accelerator in order to deliver a 4 GeV electron beam to the undulators hall. These 35 cryomodules will consist of 8 1.3 GHz TESLA style SRF cavities, a design most recently used for the XFEL project in Hamburg, Germany. The cavity design has remained largely unchanged, but the cavity treatment has been modified to utilize the nitrogen doping process to allow for Quality factors in excess of 3x10 at 16 MV/m, the designed operating gradient of the cavities in the CM at 2.0K. Two European vendors are producing most of the SRF cavities for these cryomodules; and the performance of the first article cavities, 16 from each vendor, will be reported on in this paper.