Title: Voltage measurements at the vacuum post-hole convolute of the Z pulsed-power accelerator

Abstract

Presented are voltage measurements taken near the load region on the Z pulsed-power accelerator using an inductive voltage monitor (IVM). Specifically, the IVM was connected to, and thus monitored the voltage at, the bottom level of the accelerator’s vacuum double post-hole convolute. Additional voltage and current measurements were taken at the accelerator’s vacuum-insulator stack (at a radius of 1.6 m) by using standard D-dot and B-dot probes, respectively. During postprocessing, the measurements taken at the stack were translated to the location of the IVM measurements by using a lossless propagation model of the Z accelerator’s magnetically insulated transmission lines (MITLs) and a lumped inductor model of the vacuum post-hole convolute. Across a wide variety of experiments conducted on the Z accelerator, the voltage histories obtained from the IVM and the lossless propagation technique agree well in overall shape and magnitude. However, large-amplitude, high-frequency oscillations are more pronounced in the IVM records. It is unclear whether these larger oscillations represent true voltage oscillations at the convolute or if they are due to noise pickup and/or transit-time effects and other resonant modes in the IVM. Results using a transit-time-correction technique and Fourier analysis support the latter. Regardless of which interpretation is correct,more » both true voltage oscillations and the excitement of resonant modes could be the result of transient electrical breakdowns in the post-hole convolute, though more information is required to determine definitively if such breakdowns occurred. Despite the larger oscillations in the IVM records, the general agreement found between the lossless propagation results and the results of the IVM shows that large voltages are transmitted efficiently through the MITLs on Z. These results are complementary to previous studies [R.D. McBride et al., Phys. Rev. ST Accel. Beams 13, 120401 (2010)] that showed efficient transmission of large currents through the MITLs on Z. Taken together, the two studies demonstrate the overall efficient delivery of very large electrical powers through the MITLs on Z.« less

Authors:

Waisman, E. M. ^[1]; McBride, R. D. ^[1]; Cuneo, M. E. ^[1]; Wenger, D. F. ^[1]; Fowler, W. E. ^[1]; Johnson, W. A. ^[1]; Basilio, L. I. ^[1]; Coats, R. S. ^[1]; Jennings, C. A. ^[1]; Sinars, D. B. ^[1]; Vesey, R. A. ^[1]; Jones, B. ^[1]; Ampleford, D. J. ^[1]; Lemke, R. W. ^[1]; Martin, M. R. ^[1]; Schrafel, P. C. ^[2]; Lewis, S. A. ^[1]; Moore, J. K. ^[1]; Savage, M. E. ^[1]; Stygar, W. A. ^[1]

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+ Show Author Affiliations

1. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Cornell Univ., Ithaca, NY (United States)

Publication Date:

Mon Dec 08 00:00:00 EST 2014

Research Org.:

Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1141545

Alternate Identifier(s):

OSTI ID: 1214715; OSTI ID: 1214813

Report Number(s):

SAND-2014-2706J
Journal ID: ISSN 1098-4402; PRABFM; 507005

Grant/Contract Number:  

AC04-94AL85000

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Special Topics. Accelerators and Beams

Additional Journal Information:

Journal Volume: 17; Journal Issue: 12; Journal ID: ISSN 1098-4402

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

42 ENGINEERING