Author: Ng, C.-K.
Paper Title Page
MOPPC096 Multiphysics Applications of ACE3P 361
  • K.H. Lee, C. Ko, Z. Li, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California, USA
  • G. Cheng, H. Wang
    JLAB, Newport News, Virginia, USA
  Funding: Work supported by US DOE Offices of HEP, ASCR and BES under contract AC02-76SF00515.
The TEM3P module of ACE3P, a parallel finite-element electromagnetic code suite from SLAC, focuses on the multiphysics simulation capabilities, including thermal and mechanical analysis for accelerator applications. In this pa- per, thermal analysis of coupler feedthroughs to supercon- ducting rf (SRF) cavities will be presented. For the realistic simulation, internal boundary condition is implemented to capture RF heating effects on the surface shared by a di- electric and a conductor. The multiphysics simulation with TEM3P matched the measurement within 0.4%.
WEPPC086 Higher Order Modes Damping Analysis for the SPX Deflecting Cavity Cyromodule 2414
  • L. Xiao, Z. Li, C.-K. Ng
    SLAC, Menlo Park, California, USA
  • A. Nassiri, G.J. Waldschmidt, G. Wu
    ANL, Argonne, USA
  • R.A. Rimmer, H. Wang
    JLAB, Newport News, Virginia, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A single-cell superconducting deflecting cavity operating at 2.812 GHz has been proposed and designed for the Short Pulse X-ray (SPX) project for the Advanced Photon Source upgrade. A cryomodule of 4 such cavities will be needed to produce the required 2-MV deflecting voltage. Each deflecting cavity is equipped with one fundamental power coupler (FPC), one lower order mode (LOM) coupler, and two higher order mode (HOM) couplers to achieve the stringent damping requirements for the unwanted modes. The damping of the HOM/LOM modes below the beampipe cutoff has been analyzed in the single cavity geometry and shown to meet the design requirements. The HOMs above beam pipe cutoff in the 4-cavity cyromodule, however, may result in cross coupling which may affect the HOM damping and potentially trapped modes between the cavities which could produce RF heating to the beamline bellows and even be detrimental to the beam. We have evaluated the HOM damping and trapped modes in the 4-cavity cryomodule using the parallel finite element EM code ACE3P developed at SLAC. We will present the results of the cryomodule analysis in this paper.
WEPPC087 Second Harmonic Cavity Design for Project-X Main Injector 2417
  • L. Xiao, C.-K. Ng
    SLAC, Menlo Park, California, USA
  • J.E. Dey, I. Kourbanis
    Fermilab, Batavia, USA
  In order to accelerate the proposed beam intensity for Project-X, a new RF system for Main Injector (MI) will be required. A new 53 MHz first harmonic RF cavity that meets the MI requirements for Project-X has been designed. In order to reduce the peak longitudinal beam density a 106 MHz second harmonic RF system is also needed. The first harmonic RF cavity design is a quarter wave coaxial resonator with a single accelerating gap and a perpendicular biased ferrite tuner. The second harmonic RF cavity baseline design is similar to the fundamental one and scaled down from it. RF simulations and shape optimizations on the second harmonic cavity are carried out to obtain the optimal performance which meets Project-X requirements. The results are discussed and presented in this paper.  
WEPPC110 3D Simulations of Multipacting in the 56 MHz SRF Cavity 2477
  • Q. Wu, S.A. Belomestnykh
    BNL, Upton, Long Island, New York, USA
  • L. Ge, C. Ko, Z. Li, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California, USA
  Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 56 MHz SRF Quarter-Wave Resonator (QWR) is designed for RHIC as a storage cavity to improve the collider performance. 2D multipacting simulation has been done for the cavity alone. Ripples were added to the outer body of the cavity for multipacting suppression based on the simulation findings. During operation, there will be four higher order mode (HOM) couplers and a fundamental power coupler (FPC) inserted through the end ports of the cavity and a fundamental mode damper (FD) inserted through a special port on the outer body. All of these components will be exposed to high RF fields. In this presentation we compare 2D and 3D codes simulation results for multipacting in the cavity. We also report 3D simulation results for multipacting simulation at the couplers.