Development of a Superconducting RF 500 MHz Quarter Wave Resonator for Synchrotron Light Sources

in accelerators for light sources, first as passive cavities for stabilizing the beam and later in the accelerating sections. In this SBIR proposal, Niowave and Brookhaven National Lab will collaborate to adapt the quarter wave cavity geometry for use as an accelerating structure for light sources. The interaction between the electron beam and higher-order modes in the accelerating cavities can lead to beam breakup instabilities that limit the maximum current that the cavities can maintain. Quarter wave structures have a higher-order mode spectrum which differs greatly from conventional elliptically-shaped cavities, with the frequency of the first such mode almost three times higher than the fundamental. This mode is not so strongly excited by the passing electron beam, allowing higher beam currents which in turn lead to higher brightness for the light source. This SBIR proposes collaboration between Niowave, Inc. and Brookhaven National Lab on the design of a quarter wave accelerating cavity suitable for a light-source accelerator such as the NSLS-II. In Phase I, an electromagnetic design will be optimized and a conceptual plan for the insulating cryomodule will be developed. In Phase II, the niobium cavity will be fabricated and installed in the module for RF tests at cryogenic temperatures. The successful conclusion of this project puts Niowave in position to market quarter-wave accelerating systems to light source projects around the world in Phase III.