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Title: Experimental Study of Coaxial Free-Electron Maser Based on Two-Dimensional Distributed Feedback

Abstract

The first experimental study of a coaxial free-electron maser (FEM) based on two-dimensional (2D) distributed feedback is presented. A new type of cavity formed with coaxial 2D surface photonic band gap structures was used. The FEM was driven by a large diameter (7 cm), high-current (500 A), annular electron beam of energy 475 keV. By tuning the amplitude of the undulator or guide magnetic field, modes associated with the different band gaps of the 2D structures were excited. The Ka-band coaxial FEM generated 15 MW of radiation with a 6% conversion efficiency, in excellent agreement with theory.

Authors:
; ; ; ; ; ; ;  [1]
  1. SUPA, Department of Physics, University of Strathclyde, Glasgow G4 ONG (United Kingdom)
Publication Date:
OSTI Identifier:
20776987
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevLett.96.035002; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 43 PARTICLE ACCELERATORS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ELECTRIC CURRENTS; ELECTRON BEAMS; ELECTRONS; FEEDBACK; FREE ELECTRON LASERS; KEV RANGE 100-1000; MAGNETIC FIELDS; MASERS; TWO-DIMENSIONAL CALCULATIONS; WIGGLER MAGNETS

Citation Formats

Konoplev, I.V., McGrane, P., He, W., Cross, A.W., Phelps, A.D.R., Whyte, C.G., Ronald, K., and Robertson, C.W.. Experimental Study of Coaxial Free-Electron Maser Based on Two-Dimensional Distributed Feedback. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.96.035002.
Konoplev, I.V., McGrane, P., He, W., Cross, A.W., Phelps, A.D.R., Whyte, C.G., Ronald, K., & Robertson, C.W.. Experimental Study of Coaxial Free-Electron Maser Based on Two-Dimensional Distributed Feedback. United States. doi:10.1103/PhysRevLett.96.035002.
Konoplev, I.V., McGrane, P., He, W., Cross, A.W., Phelps, A.D.R., Whyte, C.G., Ronald, K., and Robertson, C.W.. Fri . "Experimental Study of Coaxial Free-Electron Maser Based on Two-Dimensional Distributed Feedback". United States. doi:10.1103/PhysRevLett.96.035002.
@article{osti_20776987,
title = {Experimental Study of Coaxial Free-Electron Maser Based on Two-Dimensional Distributed Feedback},
author = {Konoplev, I.V. and McGrane, P. and He, W. and Cross, A.W. and Phelps, A.D.R. and Whyte, C.G. and Ronald, K. and Robertson, C.W.},
abstractNote = {The first experimental study of a coaxial free-electron maser (FEM) based on two-dimensional (2D) distributed feedback is presented. A new type of cavity formed with coaxial 2D surface photonic band gap structures was used. The FEM was driven by a large diameter (7 cm), high-current (500 A), annular electron beam of energy 475 keV. By tuning the amplitude of the undulator or guide magnetic field, modes associated with the different band gaps of the 2D structures were excited. The Ka-band coaxial FEM generated 15 MW of radiation with a 6% conversion efficiency, in excellent agreement with theory.},
doi = {10.1103/PhysRevLett.96.035002},
journal = {Physical Review Letters},
number = 3,
volume = 96,
place = {United States},
year = {Fri Jan 27 00:00:00 EST 2006},
month = {Fri Jan 27 00:00:00 EST 2006}
}
  • The first operation of a coaxial free-electron maser (FEM) based on two-dimensional (2D) distributed feedback has been recently observed. Analytical and numerical modeling, as well as measurements, of microwave radiation generated by a FEM with a cavity defined by coaxial structures with a 2D periodic perturbation on the inner surfaces of the outer conductor were carried out. The two-mirror cavity was formed with two 2D periodic structures separated by a central smooth section of coaxial waveguide. The FEM was driven by a large diameter (7 cm), high-current (500 A), annular electron beam with electron energy of 475 keV. Studies ofmore » the FEM operation have been conducted. It has been demonstrated that by tuning the amplitude of the undulator or guide magnetic field, modes associated with the different band gaps of the 2D structures were excited. The Ka-band FEM generated 15 MW of radiation with a 6% conversion efficiency, in good agreement with theory.« less
  • The study of a coaxial free-electron maser (FEM) based on two-dimensional (2D) and one-dimensional (1D) distributed feedback, driven by a 70 mm diameter, annular electron beam is presented. A new cavity formed with 2D and 1D periodic lattices, positioned at the input and output of the interaction region, respectively, was used. It has been demonstrated that 2D distributed feedback in the input mirror allowed 8 mm radiation emitted from different parts of the electron beam to be synchronized. The FEM operating in the 35.9-38.9 GHz frequency region generated 65 MW, 150 ns duration millimeter wave pulses which contained {approx}10 Jmore » of energy in the pulse.« less
  • The first successful experimental studies of microwave radiation from a co-axial Free-Electron Maser (FEM) based on two-dimensional (2D) distributed feedback have been recently conducted. This paper contains a description of the experimental set-up and the results obtained. The high-power pulsed power supply and high-current accelerator (HCA) developed and used to drive the FEM are discussed. The results of the experimental study of the FEM operating in the Ka frequency band are presented and compared with theoretical predictions.
  • Two-dimensional distributed feedback is proposed in order to obtain a spatially-coherent radiation of ribbon relativistic electron beams (REB) with transverse dimensions several orders of magnitude larger than the radiation wavelength. The feedback is provided by means of a two-dimensional Bragg resonator. The resonator consists of two metal plates with biperiodically corrugated side walls, the plates being parallel to the beam. The transverse electromagnetic energy flows arising in the resonator serve to synchronize the radiation emitted by individual beam segments. The resonator eigenmodes are found. The selective properties of the resonator are also studied. The excitation process of the 2-D Braggmore » resonator was computer simulated. The simulation results show the possibility of obtaining a coherent single mode generation using a ribbon electron beam with transverse dimensions on the order of (10{sup 2}-10{sup 3}) wavelengths. The concept of an ultrahigh-power millimeter-range free-electron laser (FEL) of 20 GW output power is presented. A ribbon REB 140 cm in width produced by the U-2 accelerator is proposed for FEL pumping. 11 refs., 7 figs.« less
  • We report on a process to design highly ordered monolayers of two-dimensional photonic crystals, made of silica nanoparticules, that can be used for the development of organic optical devices. We have used a photopolymerization process to incorporate a dye gain medium into the nanoparticle layers in order to achieve a laser cavity. The high spatial coherence of the deposits allows for single-mode laser emission in the plane of the layer when the light excitation is perpendicular to the plane. Such periodic films should help in reducing the number of layers needed for future electrically pumped distributed feedback lasers.