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Title: Characterization of x-ray imaging crystal spectrometer for high-resolution spatially-resolved x-ray Thomson scattering measurements in shock-compressed experiments

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1360786
DOE Contract Number:
AC02-09CH-11466; AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Quantitative Spectroscopy and Radiative Transfer; Journal Volume: 187; Journal Issue: C
Country of Publication:
United States
Language:
English

Citation Formats

Lu, J., Hill, K. W., Bitter, M., Pablant, N. A., Delgado-Aparicio, L. F., Efthimion, P. C., Lee, H. J., and Zastrau, U.. Characterization of x-ray imaging crystal spectrometer for high-resolution spatially-resolved x-ray Thomson scattering measurements in shock-compressed experiments. United States: N. p., 2017. Web. doi:10.1016/j.jqsrt.2016.10.001.
Lu, J., Hill, K. W., Bitter, M., Pablant, N. A., Delgado-Aparicio, L. F., Efthimion, P. C., Lee, H. J., & Zastrau, U.. Characterization of x-ray imaging crystal spectrometer for high-resolution spatially-resolved x-ray Thomson scattering measurements in shock-compressed experiments. United States. doi:10.1016/j.jqsrt.2016.10.001.
Lu, J., Hill, K. W., Bitter, M., Pablant, N. A., Delgado-Aparicio, L. F., Efthimion, P. C., Lee, H. J., and Zastrau, U.. Sun . "Characterization of x-ray imaging crystal spectrometer for high-resolution spatially-resolved x-ray Thomson scattering measurements in shock-compressed experiments". United States. doi:10.1016/j.jqsrt.2016.10.001.
@article{osti_1360786,
title = {Characterization of x-ray imaging crystal spectrometer for high-resolution spatially-resolved x-ray Thomson scattering measurements in shock-compressed experiments},
author = {Lu, J. and Hill, K. W. and Bitter, M. and Pablant, N. A. and Delgado-Aparicio, L. F. and Efthimion, P. C. and Lee, H. J. and Zastrau, U.},
abstractNote = {},
doi = {10.1016/j.jqsrt.2016.10.001},
journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
number = C,
volume = 187,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2017},
month = {Sun Jan 01 00:00:00 EST 2017}
}
  • A new type of high-resolution X-ray imaging crystal spectrometer is being developed to measure ion and electron temperature profiles in tokamak plasmas. The instrument is particularly valuable for diagnosing plasmas with purely Ohmic heating and rf heating, since it does not require the injection of a neutral beam - although it can also be used for the diagnosis of neutral-beam heated plasmas. The spectrometer consists of a spherically bent quartz crystal and a two-dimensional position-sensitive detector. It records spectra of helium-like argon (or krypton) from multiple sightlines through the plasma and projects a de-magnified image of a large plasma cross-sectionmore » onto the detector. The spatial resolution in the plasma is solely determined by the height of the crystal, its radius of curvature, and the Bragg angle. This new X-ray imaging crystal spectrometer may also be of interest for the diagnosis of ion temperature profiles in future large tokamaks, such as KSTAR and ITER, where the application of the presently used charge-exchange spectroscopy will be difficult, if the neutral beams do not penetrate to the plasma center. The paper presents the results from proof-of-principle experiments performed with a prototype instrument at Alcator C-Mod.« less
  • A new type of high-resolution x-ray imaging crystal spectrometer is being developed to measure ion and electron temperature profiles in tokamak plasmas. The instrument is particularly valuable for diagnosing plasmas with purely ohmic heating and rf heating, since it does not require the injection of a neutral beam--although it can also be used for the diagnosis of neutral-beam heated plasmas. The spectrometer consists of a spherically bent quartz crystal and a two-dimensional position-sensitive detector. It records spectra of helium-like argon (or krypton) from multiple sightlines through the plasma and projects a de-magnified image of a large plasma cross section ontomore » the detector. The spatial resolution in the plasma is solely determined by the height of the crystal, its radius of curvature, and the Bragg angle. This new x-ray imaging crystal spectrometer may also be of interest for the diagnosis of ion temperature profiles in future large tokamaks, the Korea Superconducting Tokamak Advanced Research tokamak and the International Thermonuclear Experimental Reactor, where the application of the presently used charge-exchange spectroscopy will be difficult, if the neutral beams do not penetrate to the plasma center. The article presents the results from proof-of-principle experiments performed with a prototype instrument at Alcator C-Mod.« less
  • A high resolution 1D imaging x-ray spectrometer concept comprising a spherically bent crystal and a 2D pixelated detector is being optimized for diagnostics of small sources such as high energy density physics (HEDP) and synchrotron radiation or x-ray free electron laser experiments. This instrument is used on tokamak experiments for Doppler measurements of ion temperature and plasma flow velocity profiles. Laboratory measurements demonstrate a resolving power, E/ΔE of order 10 000 and spatial resolution better than 10 μm. Initial tests of the high resolution instrument on HEDP plasmas are being performed.
  • Spectrally resolved scattering of ultra-short pulse laser-generated K-{alpha} x rays has been applied to measure the heating and compression of shocked solid-density lithium hydride. Two shocks launched by a nanosecond laser pulse coalesce yielding pressures of 400 gigapascals. The evolution of the intensity of the elastic (Rayleigh) scattering component indicates rapid heating to temperatures of 25,000 K on a 100 ps time scale. At shock coalescence, the scattering spectra show the collective plasmon oscillations indicating the transition to the dense metallic plasma state. The plasmon frequency determines the material compression, which is found to be a factor of three therebymore » reaching conditions in the laboratory important for studying astrophysics phenomena.« less