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Title: Demonstration of a long pulse X-ray source at the National Ignition Facility

Authors:
 [1]; ORCiD logo [2];  [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [3];  [1];  [3]
  1. Lawrence Livermore National Laboratory, P.O. Box 808 L170, Livermore, California 94551, USA
  2. National Security Technologies, LLC, 161S Vasco Rd., Livermore, California 94551, USA
  3. Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1363697
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 4; Related Information: CHORUS Timestamp: 2018-02-14 15:48:57; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

May, M. J., Opachich, Y. P., Kemp, G. E., Colvin, J. D., Barrios, M. A., Widmann, K. W., Fournier, K. B., Hohenberger, M., Albert, F., and Regan, S. P.. Demonstration of a long pulse X-ray source at the National Ignition Facility. United States: N. p., 2017. Web. doi:10.1063/1.4979172.
May, M. J., Opachich, Y. P., Kemp, G. E., Colvin, J. D., Barrios, M. A., Widmann, K. W., Fournier, K. B., Hohenberger, M., Albert, F., & Regan, S. P.. Demonstration of a long pulse X-ray source at the National Ignition Facility. United States. doi:10.1063/1.4979172.
May, M. J., Opachich, Y. P., Kemp, G. E., Colvin, J. D., Barrios, M. A., Widmann, K. W., Fournier, K. B., Hohenberger, M., Albert, F., and Regan, S. P.. Sat . "Demonstration of a long pulse X-ray source at the National Ignition Facility". United States. doi:10.1063/1.4979172.
@article{osti_1363697,
title = {Demonstration of a long pulse X-ray source at the National Ignition Facility},
author = {May, M. J. and Opachich, Y. P. and Kemp, G. E. and Colvin, J. D. and Barrios, M. A. and Widmann, K. W. and Fournier, K. B. and Hohenberger, M. and Albert, F. and Regan, S. P.},
abstractNote = {},
doi = {10.1063/1.4979172},
journal = {Physics of Plasmas},
number = 4,
volume = 24,
place = {United States},
year = {Sat Apr 01 00:00:00 EDT 2017},
month = {Sat Apr 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4979172

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

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  • Here, indirect drive experiments at the National Ignition Facility are designed to achieve fusion by imploding a fuel capsule with x rays from a laser-driven hohlraum. Previous experiments have been unable to determine whether a deficit in measured ablator implosion velocity relative to simulations is due to inadequate models of the hohlraum or ablator physics. ViewFactor experiments allow for the first time a direct measure of the x-ray drive from the capsule point of view. The experiments show a 15%–25% deficit relative to simulations and thus explain nearly all of the disagreement with the velocity data. In addition, the datamore » from this open geometry provide much greater constraints on a predictive model of laser-driven hohlraum performance than the nominal ignition target.« less
  • We report results from a five shot campaign carried out with Ar-Xe gas-filled targets at the National Ignition Facility (NIF). The targets were shot with {approx_equal}350 kJ of 3{omega} laser energy delivered with a 5 ns trapezoidal laser pulse. We report measured x-ray output from the target in different spectral bands both below and above 1.5 keV photon energies: We find yields of {approx_equal}20.5 kJ/sr with peak x-ray power approaching 4 TW/sr over all energies, as measured for the unique viewing angle of our detector, and {approx_equal}3.6 kJ/sr with peak x-ray power of 1 TW/sr for x-rays with energies >3more » keV. This is a laser-to-x-ray conversion efficiency of 13{+-}1.3% for isotropic x-rays with energies >3 keV. Laser energy reflected by the target plasma for both inner and outer-cone beams is measured and found to be small, between 1% and 4% of the drive energy. The energy emitted in hard x-rays (with energies >25 keV) is measured and found to be {approx_equal}1 J/sr. Two-dimensional imaging of the target plasma during the laser pulse confirms a fast, volumetric heating of the entire target, resulting in efficient laser-to-x-ray conversion. Postshot simulations with a two-dimensional radiation-hydrodynamics code reproduce well the observed x-ray flux and fluence, backscattered light, and bulk target motion.« less
  • High x-ray conversion efficiency (XRCE) K-shell sources are being developed for high energy density experiments for use as backlighters and for the testing of materials exposed to high x-ray fluxes and fluences. Recently, sources with high XRCE in the K-shell x-ray energy range of iron and nickel were investigated at the National Ignition Facility (NIF). The x-ray conversion efficiency in the 5–9 keV spectral range was determined to be 6.8% ± 0.3%. These targets were 4.1 mm diameter, 4 mm tall hollow epoxy tubes having a 50 μm thick wall supporting a tube of 3 to 3.5 μm thick stainless steel. The NIF laser deposited ∼460 kJ ofmore » 3ω light into the target in a 140 TW, 3.3 ns square pulse. The absolute x-ray emission of the source was measured by two calibrated Dante x-ray spectrometers. Time resolved images filtered for the Fe K-shell were recorded to follow the heating of the target. Time integrated high-resolution spectra were recorded in the K-shell range.« less