Free-electron masers based on two-dimensional distributed feedback

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

The results of experimental studies of a coaxial free-electron masers (FEM) based on two-dimensional distributed feedback are presented. In the first set of experiments the FEM's interaction region was formed by a two-mirror cavity with 2D Bragg structures as input and output mirrors. In the second set of experiments a cavity with 2D and 1D mirrors was used. In both cases the input mirror provided two-dimensional (2D) distributed feedback and ensured mode selection over the wave azimuthal index, while the output mirror was used to close the feedback loop inside the two-mirror cavity. It was demonstrated that substituting the 2D output mirror with a 1D Bragg structure increased the output power while still maintaining spectral purity and spatial and temporal coherence. The FEM has been driven by an oversized high-current (1.5 kA) thin annular electron beam of 200 ns pulse duration. An maximum output power of ~60 MW corresponding to an efficiency of 10% was measured for an FEM based on 2D/1D cavity. The directional mode pattern of the microwave radiation from the output horn was also measured and compared with theoretical prediction. Analysing the spectrum of the RF signal the location of the operating frequency was found.
LanguageEnglish
Title of host publication IEEE International Vacuum Electronics Conference, 2007
Subtitle of host publicationIVEC '07
Place of PublicationPiscataway, New Jersey
PublisherIEEE
Pages423-424
Number of pages2
ISBN (Print)1-4244-0633-1
DOIs
Publication statusPublished - May 2007

Publication series

NameInternational Vacuum Electronics Conference IVEC
PublisherIEEE

Fingerprint

Masers
masers
free electrons
Mirrors
mirrors
Feedback
Electrons
output
cavities
Electron beams
Experiments
Microwaves
Finite element method
high current
purity
pulse duration
electron beams
microwaves
predictions

Keywords

  • Bragg gratings
  • electron beams
  • feedback
  • masers
  • mirrors
  • annular electron beam
  • coaxial free-electron masers
  • microwave radiation pattern
  • spatial coherence
  • spectral purity

Cite this

Phelps, A. D. R., Konoplev, I. V., Cross, A. W., Macinnes, P., He, W., Ronald, K., ... Robertson, C. W. (2007). Free-electron masers based on two-dimensional distributed feedback. In IEEE International Vacuum Electronics Conference, 2007 : IVEC '07 (pp. 423-424). (International Vacuum Electronics Conference IVEC). Piscataway, New Jersey: IEEE. https://doi.org/10.1109/IVELEC.2007.4283395
Phelps, A.D.R. ; Konoplev, I.V. ; Cross, A.W. ; Macinnes, Philip ; He, W. ; Ronald, K. ; Whyte, C.G. ; Robertson, C.W. / Free-electron masers based on two-dimensional distributed feedback. IEEE International Vacuum Electronics Conference, 2007 : IVEC '07. Piscataway, New Jersey : IEEE, 2007. pp. 423-424 (International Vacuum Electronics Conference IVEC).
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abstract = "The results of experimental studies of a coaxial free-electron masers (FEM) based on two-dimensional distributed feedback are presented. In the first set of experiments the FEM's interaction region was formed by a two-mirror cavity with 2D Bragg structures as input and output mirrors. In the second set of experiments a cavity with 2D and 1D mirrors was used. In both cases the input mirror provided two-dimensional (2D) distributed feedback and ensured mode selection over the wave azimuthal index, while the output mirror was used to close the feedback loop inside the two-mirror cavity. It was demonstrated that substituting the 2D output mirror with a 1D Bragg structure increased the output power while still maintaining spectral purity and spatial and temporal coherence. The FEM has been driven by an oversized high-current (1.5 kA) thin annular electron beam of 200 ns pulse duration. An maximum output power of ~60 MW corresponding to an efficiency of 10{\%} was measured for an FEM based on 2D/1D cavity. The directional mode pattern of the microwave radiation from the output horn was also measured and compared with theoretical prediction. Analysing the spectrum of the RF signal the location of the operating frequency was found.",
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author = "A.D.R. Phelps and I.V. Konoplev and A.W. Cross and Philip Macinnes and W. He and K. Ronald and C.G. Whyte and C.W. Robertson",
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Phelps, ADR, Konoplev, IV, Cross, AW, Macinnes, P, He, W, Ronald, K, Whyte, CG & Robertson, CW 2007, Free-electron masers based on two-dimensional distributed feedback. in IEEE International Vacuum Electronics Conference, 2007 : IVEC '07. International Vacuum Electronics Conference IVEC, IEEE, Piscataway, New Jersey, pp. 423-424. https://doi.org/10.1109/IVELEC.2007.4283395

Free-electron masers based on two-dimensional distributed feedback. / Phelps, A.D.R.; Konoplev, I.V.; Cross, A.W.; Macinnes, Philip; He, W.; Ronald, K.; Whyte, C.G.; Robertson, C.W.

IEEE International Vacuum Electronics Conference, 2007 : IVEC '07. Piscataway, New Jersey : IEEE, 2007. p. 423-424 (International Vacuum Electronics Conference IVEC).

Research output: Chapter in Book/Report/Conference proceedingChapter

TY - CHAP

T1 - Free-electron masers based on two-dimensional distributed feedback

AU - Phelps, A.D.R.

AU - Konoplev, I.V.

AU - Cross, A.W.

AU - Macinnes, Philip

AU - He, W.

AU - Ronald, K.

AU - Whyte, C.G.

AU - Robertson, C.W.

PY - 2007/5

Y1 - 2007/5

N2 - The results of experimental studies of a coaxial free-electron masers (FEM) based on two-dimensional distributed feedback are presented. In the first set of experiments the FEM's interaction region was formed by a two-mirror cavity with 2D Bragg structures as input and output mirrors. In the second set of experiments a cavity with 2D and 1D mirrors was used. In both cases the input mirror provided two-dimensional (2D) distributed feedback and ensured mode selection over the wave azimuthal index, while the output mirror was used to close the feedback loop inside the two-mirror cavity. It was demonstrated that substituting the 2D output mirror with a 1D Bragg structure increased the output power while still maintaining spectral purity and spatial and temporal coherence. The FEM has been driven by an oversized high-current (1.5 kA) thin annular electron beam of 200 ns pulse duration. An maximum output power of ~60 MW corresponding to an efficiency of 10% was measured for an FEM based on 2D/1D cavity. The directional mode pattern of the microwave radiation from the output horn was also measured and compared with theoretical prediction. Analysing the spectrum of the RF signal the location of the operating frequency was found.

AB - The results of experimental studies of a coaxial free-electron masers (FEM) based on two-dimensional distributed feedback are presented. In the first set of experiments the FEM's interaction region was formed by a two-mirror cavity with 2D Bragg structures as input and output mirrors. In the second set of experiments a cavity with 2D and 1D mirrors was used. In both cases the input mirror provided two-dimensional (2D) distributed feedback and ensured mode selection over the wave azimuthal index, while the output mirror was used to close the feedback loop inside the two-mirror cavity. It was demonstrated that substituting the 2D output mirror with a 1D Bragg structure increased the output power while still maintaining spectral purity and spatial and temporal coherence. The FEM has been driven by an oversized high-current (1.5 kA) thin annular electron beam of 200 ns pulse duration. An maximum output power of ~60 MW corresponding to an efficiency of 10% was measured for an FEM based on 2D/1D cavity. The directional mode pattern of the microwave radiation from the output horn was also measured and compared with theoretical prediction. Analysing the spectrum of the RF signal the location of the operating frequency was found.

KW - Bragg gratings

KW - electron beams

KW - feedback

KW - masers

KW - mirrors

KW - annular electron beam

KW - coaxial free-electron masers

KW - microwave radiation pattern

KW - spatial coherence

KW - spectral purity

UR - http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=4283183

U2 - 10.1109/IVELEC.2007.4283395

DO - 10.1109/IVELEC.2007.4283395

M3 - Chapter

SN - 1-4244-0633-1

T3 - International Vacuum Electronics Conference IVEC

SP - 423

EP - 424

BT - IEEE International Vacuum Electronics Conference, 2007

PB - IEEE

CY - Piscataway, New Jersey

ER -

Phelps ADR, Konoplev IV, Cross AW, Macinnes P, He W, Ronald K et al. Free-electron masers based on two-dimensional distributed feedback. In IEEE International Vacuum Electronics Conference, 2007 : IVEC '07. Piscataway, New Jersey: IEEE. 2007. p. 423-424. (International Vacuum Electronics Conference IVEC). https://doi.org/10.1109/IVELEC.2007.4283395