Numerical optimization of a multistage depressed collector with secondary electron emission for an X-band gyro-BWO

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Abstract

A three-stage depressed collector was previously designed and simulated to recover the kinetic energy of the spent electron beam in an X-band gyrotron backward wave oscillator (gyro-BWO) by using the 3-D particle-in-cell code MAGIC. The geometry of the depressed collector was optimized using a genetic algorithm to achieve the optimum overall recovery efficiency for specific parameters of the spent beam. In this paper, secondary electron emissions were simulated, and a few emission models were compared to investigate the effects of the secondary electrons on the overall recovery efficiency and the backstreaming of the electrons from the collector region. The optimization of the shape and dimensions of each stage of the collector using a genetic algorithm achieved an overall recovery efficiency of more than 80% over the entire operating regime of the Gyro-BWO, with a minimized backstreaming of 1.4%. The heat distribution on the collector was calculated, and the maximum heat density on the electrodes was approximately 195 W/cm2, hence avoiding the generation of ¿hot spots¿.
LanguageEnglish
Pages2328-2334
Number of pages7
JournalIEEE Transactions on Plasma Science
Volume37
Issue number12
DOIs
Publication statusPublished - Dec 2009

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backward waves
secondary emission
superhigh frequencies
accumulators
electron emission
oscillators
optimization
recovery
genetic algorithms
heat
electrons
kinetic energy
electron beams
electrodes
geometry

Keywords

  • depressed collector
  • gyrotron backward wave oscillator
  • (Gyro-BWO)
  • heat distribution
  • secondary electron emission

Cite this

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title = "Numerical optimization of a multistage depressed collector with secondary electron emission for an X-band gyro-BWO",
abstract = "A three-stage depressed collector was previously designed and simulated to recover the kinetic energy of the spent electron beam in an X-band gyrotron backward wave oscillator (gyro-BWO) by using the 3-D particle-in-cell code MAGIC. The geometry of the depressed collector was optimized using a genetic algorithm to achieve the optimum overall recovery efficiency for specific parameters of the spent beam. In this paper, secondary electron emissions were simulated, and a few emission models were compared to investigate the effects of the secondary electrons on the overall recovery efficiency and the backstreaming of the electrons from the collector region. The optimization of the shape and dimensions of each stage of the collector using a genetic algorithm achieved an overall recovery efficiency of more than 80{\%} over the entire operating regime of the Gyro-BWO, with a minimized backstreaming of 1.4{\%}. The heat distribution on the collector was calculated, and the maximum heat density on the electrodes was approximately 195 W/cm2, hence avoiding the generation of {\~A}‚{\^A}¿hot spots{\~A}‚{\^A}¿.",
keywords = "depressed collector, gyrotron backward wave oscillator, (Gyro-BWO), heat distribution, secondary electron emission",
author = "Liang Zhang and Wenlong He and Cross, {Adrian W.} and Phelps, {Alan D. R.} and Kevin Ronald and Whyte, {Colin G.}",
year = "2009",
month = "12",
doi = "10.1109/TPS.2009.2034164",
language = "English",
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pages = "2328--2334",
journal = "IEEE Transactions on Plasma Science",
issn = "0093-3813",
number = "12",

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T1 - Numerical optimization of a multistage depressed collector with secondary electron emission for an X-band gyro-BWO

AU - Zhang, Liang

AU - He, Wenlong

AU - Cross, Adrian W.

AU - Phelps, Alan D. R.

AU - Ronald, Kevin

AU - Whyte, Colin G.

PY - 2009/12

Y1 - 2009/12

N2 - A three-stage depressed collector was previously designed and simulated to recover the kinetic energy of the spent electron beam in an X-band gyrotron backward wave oscillator (gyro-BWO) by using the 3-D particle-in-cell code MAGIC. The geometry of the depressed collector was optimized using a genetic algorithm to achieve the optimum overall recovery efficiency for specific parameters of the spent beam. In this paper, secondary electron emissions were simulated, and a few emission models were compared to investigate the effects of the secondary electrons on the overall recovery efficiency and the backstreaming of the electrons from the collector region. The optimization of the shape and dimensions of each stage of the collector using a genetic algorithm achieved an overall recovery efficiency of more than 80% over the entire operating regime of the Gyro-BWO, with a minimized backstreaming of 1.4%. The heat distribution on the collector was calculated, and the maximum heat density on the electrodes was approximately 195 W/cm2, hence avoiding the generation of ¿hot spots¿.

AB - A three-stage depressed collector was previously designed and simulated to recover the kinetic energy of the spent electron beam in an X-band gyrotron backward wave oscillator (gyro-BWO) by using the 3-D particle-in-cell code MAGIC. The geometry of the depressed collector was optimized using a genetic algorithm to achieve the optimum overall recovery efficiency for specific parameters of the spent beam. In this paper, secondary electron emissions were simulated, and a few emission models were compared to investigate the effects of the secondary electrons on the overall recovery efficiency and the backstreaming of the electrons from the collector region. The optimization of the shape and dimensions of each stage of the collector using a genetic algorithm achieved an overall recovery efficiency of more than 80% over the entire operating regime of the Gyro-BWO, with a minimized backstreaming of 1.4%. The heat distribution on the collector was calculated, and the maximum heat density on the electrodes was approximately 195 W/cm2, hence avoiding the generation of ¿hot spots¿.

KW - depressed collector

KW - gyrotron backward wave oscillator

KW - (Gyro-BWO)

KW - heat distribution

KW - secondary electron emission

U2 - 10.1109/TPS.2009.2034164

DO - 10.1109/TPS.2009.2034164

M3 - Article

VL - 37

SP - 2328

EP - 2334

JO - IEEE Transactions on Plasma Science

T2 - IEEE Transactions on Plasma Science

JF - IEEE Transactions on Plasma Science

SN - 0093-3813

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