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Title: Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility

Abstract

The solid debris collection capability at the National Ignition Facility has been expanded to include a third line-of-sight assembly. The solid radiochemistry nuclear diagnostic measurement of the ratio of gold isotopes is dependent on the efficient collection of neutron-activated hohlraum debris by passive metal disks. As a result, the collection of target debris at this new location is more reliable in comparison to the historic locations, and it appears to be independent of collector surface ablation.

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [1];  [1];  [1]; ORCiD logo [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1324511
Report Number(s):
LLNL-JRNL-694182
Journal ID: ISSN 0034-6748; RSINAK; TRN: US1700094
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 87; Journal Issue: 11; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; gold; graphite; Hohlraum; neutron diagnostics; neutrons

Citation Formats

Gharibyan, N., Shaughnessy, D. A., Moody, K. J., Grant, P. M., Despotopulos, J. D., Faye, S. A., Jedlovec, D. R., and Yeamans, C. B.. Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility. United States: N. p., 2016. Web. doi:10.1063/1.4960316.
Gharibyan, N., Shaughnessy, D. A., Moody, K. J., Grant, P. M., Despotopulos, J. D., Faye, S. A., Jedlovec, D. R., & Yeamans, C. B.. Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility. United States. doi:10.1063/1.4960316.
Gharibyan, N., Shaughnessy, D. A., Moody, K. J., Grant, P. M., Despotopulos, J. D., Faye, S. A., Jedlovec, D. R., and Yeamans, C. B.. 2016. "Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility". United States. doi:10.1063/1.4960316. https://www.osti.gov/servlets/purl/1324511.
@article{osti_1324511,
title = {Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility},
author = {Gharibyan, N. and Shaughnessy, D. A. and Moody, K. J. and Grant, P. M. and Despotopulos, J. D. and Faye, S. A. and Jedlovec, D. R. and Yeamans, C. B.},
abstractNote = {The solid debris collection capability at the National Ignition Facility has been expanded to include a third line-of-sight assembly. The solid radiochemistry nuclear diagnostic measurement of the ratio of gold isotopes is dependent on the efficient collection of neutron-activated hohlraum debris by passive metal disks. As a result, the collection of target debris at this new location is more reliable in comparison to the historic locations, and it appears to be independent of collector surface ablation.},
doi = {10.1063/1.4960316},
journal = {Review of Scientific Instruments},
number = 11,
volume = 87,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

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  • Here, the National Ignition Facility (NIF) is a 192 laser beam facility designed to support the Stockpile Stewardship, High Energy Density and Inertial Confinement Fusion (ICF) programs. We report on the design of an Optical Thomson Scattering (OTS) diagnostic that has the potential to transform the community’s understanding of NIF hohlraum physics by providing first principle, local, time-resolved measurements of under-dense plasma conditions. The system design allows operation with different probe laser wavelengths by manual selection of the appropriate beam splitter and gratings before the shot. A deep-UV probe beam (λ 0-210 nm) will be used to optimize the scatteredmore » signal for plasma densities of 5 × 10 20 electrons/cm 3 while a 3ω probe will be used for experiments investigating lower density plasmas of 1 × 10 19 electrons/cm 3. We report the phase I design of a two phase design strategy. Phase I includes the OTS telescope, spectrometer, and streak camera; these will be used to assess the background levels at NIF. Phase II will include the design and installation of a probe laser.« less
  • Beamlet is a single-aperture beamline Nd:Glass laser system that functions as a scientific prototype of a new class of fusion laser drivers. Its architecture is based on the use of components with a single aperture size. The beam propagates multiple passes through the largest aperture amplifier. The National Ignition Facility laser driver design applies this architecture to deliver 1.8 MJ of 351 nm light using 192 beams, for the purpose of achieving ignition and thermonuclear burn of ICF targets. 15 refs., 6 figs.
  • In 2010, the National Ignition Facility (NIF) is scheduled to achieve ignition. We propose radiochemistry of the fusion bum products as an attractive way to measure the amount of DT fuel that is mixed in with the surrounding ablator material. In addition, radiochemistry offers the possibility of measuring the temperature history of the DT fuel burn, the <{rho}r> of the fuel, and the neutron fluence of the 14 MeV, reaction-in-flight ('knock-on'), and low-energy neutrons. We can use prompt {beta} spectroscopy from the debris products and collection of the debris (for mass spectrometry) to make the radiochemical measurements. Radiochemistry thus offersmore » the opportunity to make unique measurements, as well as provide crosschecks with results from other diagnostics for NIF ignition capsules. We will limit our discussion here to reactions involving 0.9 atom% copper-doped beryllium ablator capsules filled with DT and gold hohlraums.« less
  • Understanding mix in inertial confinement fusion (ICF) experiments at the National Ignition Facility requires the diagnosis of charged-particle reactions within an imploded target. Radiochemical diagnostics of these reactions are currently under study by scientists at Los Alamos and Lawrence Livermore National Laboratories. Measurement of these reactions requires assay of activated debris and tracer gases from the target. Presented below is an overview of the prompt radiochemistry diagnostic development efforts, including a discussion of the reactions of interest as well as the progress being made to collect and count activated material.