• N.R.A. Valles, Z.A. Conway, M. Liepe
  CLASSE, Ithaca, New York

The superheating magnetic field of a superconducting niobium 1.3 GHz reentrant cavity was measured at several points in the temperature range from (1.7 to 4.4) K. This experimental data is used to discriminate between two competing theoretical s for the temperature dependent behavior of the RF superheating field. Measurements were made with <250 us high power pulses (HPP, ~1MW) to avoid defect initiated thermal breakdown from contaminating the data. Our test incorporated oscillating superleak transducers to determine the cavity quench locations and characterize changes and the migrations of the quench locations during processing. This information provides insight into the factors which limit the ultimate achievable RF surface magnetic field.

• M. Liepe, G.Q. Stedman, N.R.A. Valles
  Cornell University, Ithaca, New York

Funding: This work is supported by the National Science Foundation.

Cornell University is developing an Energy-Recovery-Linac driven x-ray light source. One of the major components of this accelerator will be its 5 GeV superconducting main linac. The design of the superconducting RF cavities in this main linac has been optimized primarily for two objectives: (1) low RF losses from the accelerating mode to minimize refrigeration cost and (2) strong Higher-Order-Mode damping to preserve low emittance and prevent beam break-up at high beam current (100 mA). In this paper we study the robustness of this optimized cavity design with respect to small cell shape fluctuations from fabrication errors.