Measurement of electron-impact ionization cross section of He-like Fe<sup>24+ </sup>

ORAL

Abstract



The electron-impact ionization cross section of He-like Fe24+ was investigated at various electron beam energies. An array of transition-edge sensor (TES) x-ray microcalorimeters[1] operated at the NIST EBIT facility covered the 500 eV to 10 keV x-ray region with an energy resolution of 5 eV. K-alpha emission lines of Mg, Al, Fe, Co, and Ni from a fluorescent source were used for calibration. Modeling was performed with the non-Maxwellian collisional-radiative code NOMAD[2] using data generated by the FAC package[3]. The ionization cross sections of He-like Fe24+ at different electron beam energies were determined from the ratio of H-like Ly-alpha and He-like w lines. Relevant collisional processes in the EBIT, including radiative recombination, electron impact excitation, and charge exchange with neutral atoms were accounted for. Comparison with theoretical calculations and consequences for the temperature diagnostics of astrophysical plasmas will be discussed.

[1] P. Szypryt et al., Rev. Sci. Instrum. 90, 123107 (2019).

[2] Yu. Ralchenko and Y. Maron, J. Quant. Spectr. Rad. Transf. 71, 609 (2001).   

[3] M. F. Gu, Can. J. Phys. 86, 675 (2008).

*Funded by NASA #80NSSC18K0234, NSF #1806494, NIST #70NANB19H024

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Presenters

  • Yang Yang

    • Clemson University

Authors

  • Yang Yang

    • Clemson University

  • Dipti Dipti

    • National Institute of Standards and Technology
    • National Institute of Standards and Technology, Gaithersburg, MD
    • National Institute of Standards and Technology, Gaithersburg, MD 20899
    • NIST

  • Amy Gall

    • Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138

  • Galen O'Neil

    • National Institute of Standards
    • National Institute of Standards and Technology
    • National Institute of Standards and Technology, Boulder, CO 80305

  • Paul Szypryt

    • National Institute of Standards and Technology
    • National Institute of Standards and Technology, Boulder, CO
    • National Institute of Standards and Technology, Boulder, CO 80305

  • Adam Hosier

    • Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978

  • Nancy Brickhouse

    • Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138

  • Randall K Smith

    • Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138

  • Adam Foster

    • Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138

  • Joseph Tan

    • National Institute of Standards and Technology
    • National Institute of Standards & Technology
    • National Institute of Standards and Technology, Gaithersburg, MD
    • National Institute of Standards and Technology, Gaithersburg, MD 20899

  • Aung S Naing

    • University of Delaware, National Institute of Standards and Technology
    • University of Delaware, National Institute of Standards & Technology
    • University of Delaware
    • National Institute of Standards and Technology, Gaithersburg, MD
    • National Institute of Standards and Technology, Gaithersburg, MD 20899

  • David R Schultz

    • Northern Arizona University

  • Yuri Ralchenko

    • National Institute of Standards and Technology

  • Endre Takacs

    • Clemson University