Physical Review Special Topics. Accelerators and Beams (Apr 2010)

10^{7}-A load-current B-dot monitor: Simulations, design, and performance

  • D. V. Rose,
  • D. R. Welch,
  • C. L. Miller,
  • R. E. Clark,
  • E. A. Madrid,
  • C. B. Mostrom,
  • T. C. Wagoner,
  • J. K. Moore,
  • W. A. Stygar,
  • J. E. Bailey,
  • T. J. Nash,
  • G. A. Rochau,
  • D. B. Sinars

DOI
https://doi.org/10.1103/PhysRevSTAB.13.040401
Journal volume & issue
Vol. 13, no. 4
p. 040401

Abstract

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A B-dot monitor that measures the current 6 cm from the axis of dynamic loads fielded on 10^{7}-A multiterawatt pulsed-power accelerators has been developed. The monitor improves upon the multimegampere load-current gauge described in Phys. Rev. ST Accel. Beams 11, 100401 (2008)PRABFM1098-440210.1103/PhysRevSTAB.11.100401. The design of the improved monitor was developed using three-dimensional particle-in-cell simulations that model vacuum electron flow in the transmission line near the monitor. The simulations include important geometric features of the B-dot probe and model the deposition of electron energy within the probe. The simulations show that the improved design reduces by as much as a factor of 5 the electron energy deposition to the interior of the monitor. Data taken on accelerator shots demonstrate that the improved monitor works as well as the original monitor on shots with low-impedance loads, and delivers superior performance on higher-impedance-load shots.