• R.A. Rimmer, W.A. Clemens, J. Henry, P. Kneisel, K. Macha, F. Marhauser, L. Turlington, H. Wang
  JLAB, Newport News, Virginia

JLab has designed and fabricated several prototype SRF cavities with cell shapes optimized for high current beams and with strong damping of unwanted higher order modes. We report on the latest test results of these cavities and on developments of concepts for new variants optimized for particular applications such as light sources and high-power proton accelerators, including betas less than one. We also report on progress towards a first beam test of this design in the recirculation loop of the JLab ERL based FEL. With growing interest worldwide in applications of SRF for high-average power electron and hadron machines, a practical test of these concepts is highly desirable. We plan to package two prototype cavities in a de-mountable cryomodule for temporary installation into the JLab FEL for testing with RF and beam. This will allow verification of all critical design and operational parameters paving the way to a full-scale prototype cryomodule.

• H. Wang, G. Cheng, G. Ciovati, J. Henry, P. Kneisel, R.A. Rimmer, G. Slack, L. Turlington
  JLAB, Newport News, Virginia
• R. Nassiri, G.J. Waldschmidt
  ANL, Argonne

A squashed, elliptical supercondconducting (SC) cavity with waveguide dampers on the beam pipes has currently been chosen as the baseline design [1] for the Short Pulse X-ray (SPX) project at the Advanced Photon Source (APS). An alternate cavity design, with a waveguide damper located directly on the cavity cell for improved damping characteristics, has also been designed and cold-tested with promising results. In either case, eight cavities would be operated CW in a single cryomodule at 2K to produce an electron bunch chirp of 4MV at a frequency of 2.815 GHz. Detailed analysis of multipactoring (MP), lorentz force detuning (LFD), and the thermal properties of the baseline design has led to an engineering specification of the basic parameters of the cryomodule.