PAC2013 - List of Authors (Hummelt, J.S.)

Paper	Title	Page
WEPBA13	Retrieval of Effective Parameters of Metamaterials for Accelerator and Vacuum Electron Device Applications	910
	Z. Duan, J.S. Hummelt, M.A. Shapiro, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA
	Funding: This work was supported by DOE, High Energy Physics (Grant No. DE-SC0010075) and the Fundamental Research Funds for the Central Universities (Grant No. ZYGX2010X010). Metamaterials (MTMs) are artificial electromagnetic materials comprised of sub-wavelength elements. A Double-Negative Metamaterial (DNM) has both negative permittivity and negative permeability and can be described by an effective medium theory. We investigate MTMs at microwave, millimeter wave, and THz frequencies for application as accelerator structures, as interaction circuits of high power microwave vacuum electron devices, and as beam diagnostics tools. In this paper, we propose a new method to retrieve the effective material parameters, i.e., effective permittivity and permeability. We first get the effective permeability analytically and then the effective permittivity numerically according to the dispersion characteristics. This method is different from that for the slab DNMs which is based on the scattering parameters. The approach presented here offers a solid foundation for metamaterial-based accelerator and vacuum electron device applications.

WEPBA14	Simulation of Wakefields from an Electron Bunch in a Metamaterial Waveguide	913
	M.A. Shapiro, J.S. Hummelt, B.J. Munroe, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA S.M. Lewis MIT, Cambridge, Massachusetts, USA
	Funding: Work supported by DOE, High Energy Physics, Grant DE-SC0010075 A metamaterial waveguide is proposed for application in a linear accelerator. The waveguide walls are made of a metamaterial that includes complementary split-ring resonators. In such a metamaterial waveguide, the TM-like mode exists and can be excited by the electron bunch. A complementary split-ring resonator is formed by slots in a metallic plate, therefore, this metamaterial waveguide is easy to build. This makes it possible to use in high frequency linear accelerators. The metamaterial waveguide is coupled to single mode rectangular waveguides which can be connected to a microwave network for coupling power into or out of the waveguide. One attractive application of the proposed metamaterial waveguide is in electron beam bunch diagnostics. The metamaterial waveguide is designed using HFSS. The wakefield simulations are carried out using the CST Particle Studio code. The simulations are done for a single bunch as well as for a train of bunches to model the experiment. In this experiment, it is proposed to use the beam line of the Haimson Research Corporation/MIT linear accelerator operating at the frequency of 17.14 GHz.

Paper

Title

Page

Retrieval of Effective Parameters of Metamaterials for Accelerator and Vacuum Electron Device Applications

910

Z. Duan, J.S. Hummelt, M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA

Funding: This work was supported by DOE, High Energy Physics (Grant No. DE-SC0010075) and the Fundamental Research Funds for the Central Universities (Grant No. ZYGX2010X010).
Metamaterials (MTMs) are artificial electromagnetic materials comprised of sub-wavelength elements. A Double-Negative Metamaterial (DNM) has both negative permittivity and negative permeability and can be described by an effective medium theory. We investigate MTMs at microwave, millimeter wave, and THz frequencies for application as accelerator structures, as interaction circuits of high power microwave vacuum electron devices, and as beam diagnostics tools. In this paper, we propose a new method to retrieve the effective material parameters, i.e., effective permittivity and permeability. We first get the effective permeability analytically and then the effective permittivity numerically according to the dispersion characteristics. This method is different from that for the slab DNMs which is based on the scattering parameters. The approach presented here offers a solid foundation for metamaterial-based accelerator and vacuum electron device applications.

WEPBA14

Simulation of Wakefields from an Electron Bunch in a Metamaterial Waveguide

913

M.A. Shapiro, J.S. Hummelt, B.J. Munroe, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
S.M. Lewis
MIT, Cambridge, Massachusetts, USA

Funding: Work supported by DOE, High Energy Physics, Grant DE-SC0010075
A metamaterial waveguide is proposed for application in a linear accelerator. The waveguide walls are made of a metamaterial that includes complementary split-ring resonators. In such a metamaterial waveguide, the TM-like mode exists and can be excited by the electron bunch. A complementary split-ring resonator is formed by slots in a metallic plate, therefore, this metamaterial waveguide is easy to build. This makes it possible to use in high frequency linear accelerators. The metamaterial waveguide is coupled to single mode rectangular waveguides which can be connected to a microwave network for coupling power into or out of the waveguide. One attractive application of the proposed metamaterial waveguide is in electron beam bunch diagnostics. The metamaterial waveguide is designed using HFSS. The wakefield simulations are carried out using the CST Particle Studio code. The simulations are done for a single bunch as well as for a train of bunches to model the experiment. In this experiment, it is proposed to use the beam line of the Haimson Research Corporation/MIT linear accelerator operating at the frequency of 17.14 GHz.