Journal Article

PUBDB-2026-00556

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Experimental electron impact ionization cross sections of Fe XXV and Maxwellian-averaged rate coefficients

Yang, Y.DESY* ; Dipti ; Foster, A. R. ; Gall, A. C. ; Brickhouse, N. ; Szypryt, P. ; O’Neil, G. C. ; Hosier, A. T. ; Naing, A. S. ; Tan, J. N. ; Schultz, D. R. ; Smith, R. K. ; Ralchenko, Y. ; Takacs, E. (Corresponding author)

2025
EDP Sciences Les Ulis

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Please use a persistent id in citations: doi:10.1051/0004-6361/202554332  doi:10.3204/PUBDB-2026-00556

Abstract: Context. Collisionally ionized plasmas produce X-ray spectra that depend on electron energy and atomic processes, requiring accurate atomic rate coefficients for modeling. While most data are theoretical, experimental measurements – such as those for Fe XXV – are critical for providing important benchmarks and quantifying uncertainties, thereby improving astrophysical spectral analysis, especially with high-resolution observatories like XRISM.Aims. This study aimed to experimentally measure the electron impact ionization (EII) cross section of Fe XXV, a key ion in astrophysical plasma diagnostics, and to evaluate the impact of these measurements on the interpretation of X-ray spectra from high-temperature plasma environments.Methods. The EII cross sections were measured using X-ray spectroscopy with an electron beam ion trap (EBIT) at various electron beam energies. The intensity ratios of the w resonance line in Fe XXV and the Lyα1,2 lines in Fe XXVI were used to derive the cross sections. Level-resolved population calculations were performed using the NOMAD collisional-radiative code to account for processes affecting the emission ratios and ionization balance in the non-Maxwellian EBIT plasma.Results. The measured EII cross sections show good agreement with relativistic convergent close-coupling calculations. The uncertainties in the measurements, ranging from 8% to 12%, are discussed in terms of their impact on the accuracy of temperature diagnostics for astrophysical plasma environments.

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Contributing Institute(s):

1. Z_DET (Z_DET)

Research Program(s):

1. 613 - Matter and Radiation from the Universe (POF4-613) (POF4-613)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2025

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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