Author: Nantista, C.D.
Paper Title Page
WEPWA068 Design Concepts for the NGLS Linac 2271
  • A. Ratti, J.M. Byrd, J.N. Corlett, L.R. Doolittle, P. Emma, J. Qiang, M. Venturini, R.P. Wells
    LBNL, Berkeley, California, USA
  • C. Adolphsen, C.D. Nantista
    SLAC, Menlo Park, California, USA
  • D. Arenius, S.V. Benson, D. Douglas, A. Hutton, G. Neil, W. Oren, G.P. Williams
    JLAB, Newport News, Virginia, USA
  • C.M. Ginsburg, R.D. Kephart, T.J. Peterson, A.I. Sukhanov
    Fermilab, Batavia, USA
  The Next Generation Light Source (NGLS) is a design concept for a multibeamline soft x-ray FEL array powered by a ~2.4 GeV CW superconducting linear accelerator, operating with a 1 MHz bunch repetition rate. This paper describes the concepts under development for a linac operating at 1.3 GHZ and based on minimal modifications to the design of ILC cryomodules in order to leverage the extensive R&D that resulted in the ILC design. Due to the different nature of the two applications, particular attention is given here to high loaded Q operation andμphonics control, as well as high reliability and expected up time.  
WEPFI080 Waveguide Component R&D for the ILC 2881
  • C.D. Nantista, C. Adolphsen, G.B. Bowden, A.A. Haase, B.D. McKee, F.Y. Wang
    SLAC, Menlo Park, California, USA
  Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515.
Several years of effort have gone into refining the design of the International Linear Collider. The direction the design has evolved in response to driving considerations has resulted in a more sophisticated waveguide system for delivering RF power to the cavities. In particular, the desire to eliminate parallel service tunnels along the main linacs led to the proposal of the Klystron Cluster Scheme (KCS)*, involving plumbing the combined power from groups of klystrons down from the surface at several locations in overmoded waveguide. Additionally, to increase superconducting cavity yield, the acceptance criteria were relaxed to encompass a ±20% range in sustainable operating gradient, which must be accommodated by tailoring of the RF power distribution. Designs and prototype testing of some of the novel waveguide components developed to allow these changes are described here.
* Christopher Nantista and Chris Adolphsen, “Klystron Cluster Scheme for ILC High Power RF Distribution,” presented at the 2009 Particle Accel. Conf., Vancouver, B.C., Canada, May 2009.
WEPFI081 High Power Tests of Overmoded Waveguide for the ILC Klystron Cluster Scheme 2884
  • F.Y. Wang, C. Adolphsen, C.D. Nantista
    SLAC, Menlo Park, California, USA
  A Klystron Cluster Scheme has been proposed for the ILC Main Linacs in which the output power of up to thirty, 10 MW, 1.3 GHz klystrons are combined in a single, 0.5 m diameter circular waveguide in a surface building and transported down to and along the accelerator tunnel where it is periodically tapped-off to power strings of cavities. This schemes eliminates the need for a separate linac service tunnel and simplifies the linac electric and cooling distribution systems. Recently, a 40 meter long circular waveguide with a coaxial input coupler and a 90 degree rf bend were assembled and run in a resonant configuration to test the concept. With the pipe pressurized with up to 30 psig of N2 to raise the rf breakdown threshold, it was demonstrated that field levels equal to those for the 300 MW transmission required for ILC could be sustained reliably. We report on these and other test results from this program.