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Title: High-Resolution Measurements of the K-Shell Spectral Lines of Hydrogenlike and Heliumlike Xenon

Abstract

With the implementation of a transmission-type curved crystal spectrometer at the Livermore high-energy electron beam ion trap (SuperEBIT) the window on sub-eV level measurements of the ground-state quantum electrodynamics and the two-electron quantum electrodynamics of high-Z ions has been opened. High-resolution spectroscopic measurements of the K{alpha} spectra of hydrogenlike Xe{sup 53+} and heliumlike Xe{sup 52+} are presented. The electron-impact excitation cross sections have been determined relative to the radiative recombination cross sections. The electron-impact energy was 112 keV which is about 3.7 times the excitation threshold for the n = 2 {yields} 1 transitions. Although the relative uncertainties of the measured electron-impact excitation cross sections range from about 20% to 50%, significant disagreement between the measured and calculated cross section values has been found for one of the heliumlike xenon lines. Overall, the comparison between experiment and theory shows that already for xenon (Z=54) the Breit interaction plays a significant part in the collisional excitation process. The measured cross sections for the hydrogenlike transitions are in good agreement with theoretical predictions. Additionally, the Xe{sup 53+} Ly-{alpha}{sub 1} transition energy has been measured utilizing the K{alpha} emission of neutral cesium and barium for calibration. Surprisingly, the experimental result, (31279.2 {+-} 1.5)more » eV, disagrees with the widely accepted theoretically predicted value of (31283.77 {+-} 0.09) eV. However, this disagreement does not (yet) call for any correction in respect to the theoretical values for the transition energies of the hydrogenlike isoelectronic sequence. It rather emphasizes the need for a reevaluation of the commonly used x-ray wavelengths table for atomic inner-shell transitions, in particular, for the cesium K{alpha} lines.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (US)
Sponsoring Org.:
USDOE Office of Defense Programs (DP) (US)
OSTI Identifier:
790856
Report Number(s):
UCRL-JC-134916
TRN: US200206%%11
DOE Contract Number:
W-7405-Eng-48
Resource Type:
Conference
Resource Relation:
Conference: 18th International Conference on X-Ray and Inner-Shell Processes, Chicago, IL (US), 08/23/1999--08/27/1999; Other Information: PBD: 13 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; CROSS SECTIONS; ELECTRON BEAMS; K SHELL; QUANTUM ELECTRODYNAMICS; SPECTROMETERS; XENON ISOTOPES

Citation Formats

Windman, K., Beiersdorfer, P., Brown, G.V., Crespo, J.R., Osterheld, A.L., Reed, K.J., Scofield, J.H., and Utter, S.B. High-Resolution Measurements of the K-Shell Spectral Lines of Hydrogenlike and Heliumlike Xenon. United States: N. p., 1999. Web.
Windman, K., Beiersdorfer, P., Brown, G.V., Crespo, J.R., Osterheld, A.L., Reed, K.J., Scofield, J.H., & Utter, S.B. High-Resolution Measurements of the K-Shell Spectral Lines of Hydrogenlike and Heliumlike Xenon. United States.
Windman, K., Beiersdorfer, P., Brown, G.V., Crespo, J.R., Osterheld, A.L., Reed, K.J., Scofield, J.H., and Utter, S.B. Mon . "High-Resolution Measurements of the K-Shell Spectral Lines of Hydrogenlike and Heliumlike Xenon". United States. doi:. https://www.osti.gov/servlets/purl/790856.
@article{osti_790856,
title = {High-Resolution Measurements of the K-Shell Spectral Lines of Hydrogenlike and Heliumlike Xenon},
author = {Windman, K. and Beiersdorfer, P. and Brown, G.V. and Crespo, J.R. and Osterheld, A.L. and Reed, K.J. and Scofield, J.H. and Utter, S.B.},
abstractNote = {With the implementation of a transmission-type curved crystal spectrometer at the Livermore high-energy electron beam ion trap (SuperEBIT) the window on sub-eV level measurements of the ground-state quantum electrodynamics and the two-electron quantum electrodynamics of high-Z ions has been opened. High-resolution spectroscopic measurements of the K{alpha} spectra of hydrogenlike Xe{sup 53+} and heliumlike Xe{sup 52+} are presented. The electron-impact excitation cross sections have been determined relative to the radiative recombination cross sections. The electron-impact energy was 112 keV which is about 3.7 times the excitation threshold for the n = 2 {yields} 1 transitions. Although the relative uncertainties of the measured electron-impact excitation cross sections range from about 20% to 50%, significant disagreement between the measured and calculated cross section values has been found for one of the heliumlike xenon lines. Overall, the comparison between experiment and theory shows that already for xenon (Z=54) the Breit interaction plays a significant part in the collisional excitation process. The measured cross sections for the hydrogenlike transitions are in good agreement with theoretical predictions. Additionally, the Xe{sup 53+} Ly-{alpha}{sub 1} transition energy has been measured utilizing the K{alpha} emission of neutral cesium and barium for calibration. Surprisingly, the experimental result, (31279.2 {+-} 1.5) eV, disagrees with the widely accepted theoretically predicted value of (31283.77 {+-} 0.09) eV. However, this disagreement does not (yet) call for any correction in respect to the theoretical values for the transition energies of the hydrogenlike isoelectronic sequence. It rather emphasizes the need for a reevaluation of the commonly used x-ray wavelengths table for atomic inner-shell transitions, in particular, for the cesium K{alpha} lines.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Sep 13 00:00:00 EDT 1999},
month = {Mon Sep 13 00:00:00 EDT 1999}
}

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