We have measured the polarization of the heliumlike sulfur resonance line $1s2p{}^{1}P_1\to 1s^2{}^{1}S_0$ and of the blend of the lithiumlike sulfur resonance lines $1s2s2p{}^{2}P_{3∕2}\to 1s^{2}2s{}^{2}S_{1∕2}$ and $1s2s2p{}^{2}P_{1∕2}\to 1s^{2}2s{}^{2}S_{1∕2}$ as a function of electron beam energy from near threshold to $144\mathrm{keV}$. These lines were excited with the LLNL high-energy electron beam ion trap and measured using a newly modified two-crystal technique. Our results test polarization predictions in an energy regime where few empirical results have been reported. We also present calculations of the polarization using two different methods, and good agreement is obtained.

• Received 12 April 2004

DOI:https://doi.org/10.1103/PhysRevA.70.022715