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Linear Polarization of Anisotropically Excited X-ray Lines from the n=2 Complex in He-like Ar16+



Dipti Goyal, Sean W. Buechele, Amy C. Gall, Samuel C. Sanders, Csilla I. Szabo-Foster, Roshani Silwal, Endre A. Takacs, Yuri Ralchenko


High-resolution x-ray spectra were recorded at the National Institute of Standards and Technology (NIST) electron beam ion trap (EBIT) using two Johann-type crystal spectrometers, with their dispersion planes oriented parallel and perpendicular to the beam direction. The linear polarizations of the 1s2 1s2l transitions in He-like argon ions were determined from the measured spectra at electron beam energies of 3.87 keV and 7.91 keV. The theoretical analysis was performed using detailed collisional-radiative modeling of the non-Maxwellian EBIT plasma with the NOMAD code modi ed to account for magnetic sublevel atomic kinetics. Effects influencing the polarizations of the observed 1s2 1s2l lines were investigated, including radiative cascades, the 1s2 1S0 1s2s 1S0 two-photon transition, and the charge exchange recombination of H-like argon ions. With these included, the measured polarizations of the resonance (1s2 1S0 .. 1s2p 1P1), intercombination (1s2 1S0 .. 1s2p 3P1), and forbidden lines (1s2 1S0 .. 1s2s 3S1, 1s2 1S0 .. 1s2p 3P2 ) were found to be in good agreement with the calculations.
Journal of Physics B-Atomic Molecular and Optical Physics


Polarization, spectroscopy, highly-charged ions, EBIT, magnetic sublevels, collisional-radiative modeling


Goyal, D. , Buechele, S. , Gall, A. , Sanders, S. , Szabo-Foster, C. , Silwal, R. , Takacs, E. and Ralchenko, Y. (2020), Linear Polarization of Anisotropically Excited X-ray Lines from the n=2 Complex in He-like Ar16+, Journal of Physics B-Atomic Molecular and Optical Physics, [online], (Accessed December 3, 2021)
Created May 13, 2020, Updated July 30, 2021