Hydrogenic Lamb shift in iron Fe{sup 25+} and fine-structure Lamb shift

Journal Article · Mon Oct 15 04:00:00 EDT 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.76.042116· OSTI ID:21020658

Chantler, C T; Laming, J M; Dietrich, D D; Hallett, W A; McDonald, R; Silver, J D ^[1]

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1. School of Physics, University of Melbourne, Victoria 3010 (Australia)

1s-2p Lyman {alpha} transitions in hydrogenic iron Fe{sup 25+} have been observed from a beam-foil source in fourth-order diffraction off ADP 101 and PET 002 crystals, simultaneously with the n=2 to n=4 Balmer {beta} transitions diffracted in first order. Calibration of the local dispersion relation of the spectrometer using Balmer {beta} lines provides measurements of Lyman {alpha} wavelengths. The approach of fitting the full two-dimensional dispersion relation, including other members of Balmer and Lyman series, limits random and systematic correlation of parameters, and reveals a major systematic due to dynamical diffraction depth penetration into a curved crystal. The development of a theory of x-ray diffraction from mosaic crystals was necessary for the accurate interpretation of the experimental data. Photographic theory was also developed in the process of this research. Several systematics are discussed and quantified for the first time for these medium-Z QED comparisons. 2s-1s and 4f-2p satellites are explicitly investigated, and a dominant systematic is uncovered, which is due to the variable location of spectral emission downstream of the beam-foil target. 1s-2p{sub 3/2}, 1s-2p{sub 1/2} iron Lamb shifts are measured to be 35 376{+-}1900 cm{sup -1} and 35 953{+-}1800 cm{sup -1}. These agree with but lie higher than theory. This represents a 5.7% measurement of the hydrogenic 1s-2p{sub 1/2} Lamb shift in iron. The technique also reports the iron 2p{sub 3/2}-2p{sub 1/2} fine structure as 171 108 cm{sup -1}{+-}180 cm{sup -1}, which represents a 51% measurement of the hydrogenic iron fine-structure Lamb shift, and reports measurements of secondary lines.

• OSTI ID: 21020658
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 76; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
CALIBRATION
CATIONS
COMPARATIVE EVALUATIONS
CORRELATIONS
DISPERSION RELATIONS
EMISSION
ENERGY-LEVEL TRANSITIONS
FINE STRUCTURE
FOILS
IRON
LAMB SHIFT
LYMAN LINES
MULTICHARGED IONS
QUANTUM ELECTRODYNAMICS
SPECTROMETERS
TWO-DIMENSIONAL CALCULATIONS
X-RAY DIFFRACTION
X-RAY SPECTRA