Author: Temkin, R.J.
Paper Title Page
TUPPR069 Calculation of Wakefields in 17-GHz Beam-Driven Photonic Bandgap Accelerator Structure 1981
  • M. Hu, B.J. Munroe, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  We present computer simulations of the wakefields in a six cell Photonic Bandgap (PBG) structure at 17GHz. Using the commercial code CST Particle Studio, the major accelerating mode (TM01) and dipole mode (TM11) are identified. The modes are excited by passing an 18MeV electron beam through the structure. The comparisons of the wakefields in an elliptical-rod PBG structure, round-rod PBG structure, and disc-loaded waveguide structure are carried out to verify experimental results. Various parameters, such as the beam charge and position, are varied to analyze the amplitude and decay time of the wakefields in the three structures. All of the simulation results will guide the design of next generation high gradient accelerator PBG structures.  
TUPPR070 High-Gradient Photonic Band-gap (PBG) Structure Breakdown Testing at Ku-Band 1984
  • B.J. Munroe, A.M. Cook, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  Photonic Band-gap (PBG) structures continue to be a promising area of research forfuture accelerator structures. Previous experiments at X-Band have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. Two single-cell standing-wave structures have been constructed at MIT to investigate breakdown performance of PBG structures. A metallic structure with small rods will be used to test performance with very high surface temperature rise, while an over-moded structure with dielectric rods will investigate alternative solutions to the issue of surface temperature rise. Both structures are expected to reach gradients of at least 100 MV/m and will utilize novel diagnostics, including fast camera imaging and optical spectroscopy of breakdowns.  
TUPPR071 Experimental High-Gradient Testing of an Elliptical-Rod Photonic Band-Gap (PBG) Structure at X-Band 1987
  • B.J. Munroe, M.A. Shapiro, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  • V.A. Dolgashev, S.G. Tantawi, A.D. Yeremian
    SLAC, Menlo Park, California, USA
  • R.A. Marsh
    LLNL, Livermore, California, USA
  An 11.4 GHz Photonic Band-gap (PBG) structure where the rods in the inner row have an elliptical cross-section has been designed at MIT and tested at high power and high repetition rate at SLAC. This structure exhibits lower surface magnetic fields on the rods relative to previous round-rod PBG structures tested at SLAC, which reduces the ohmic heating of the rod surface in an effort to reduce pulsed heating damage. This improved PBG structure was tested experimentally such as to avoid excessively high breakdown rates and surface temperature rise. The structure demonstrated performance comparable to disc-loaded waveguide (DLWG) structures with the same iris geometry, achieving greater than 100 MV/m gradient at a breakdown probability of less than 10-3 per pulse per m for 150 ns pulses. This level of performance demonstrates that elliptical-rod PBG structures could be candidates for future accelerator applications.