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In an effort to measure electron-impact ionization (EII) cross-sections of He-like Fe24+ at the electron beam ion trap (EBIT) facility of the National Institute of Standards and Technology (NIST), we have experimentally determined the corrections to the nominal beam energy determined by the voltages applied to the EBIT. High-resolution X-ray spectra were recorded at nominal electron beam energies between 6660 eV and 6750 eV using X-ray microcalorimetry based upon an array of 192 transition-edge sensors (TES). A large-scale collisional-radiative simulation of the non-Maxwellian EBIT plasma using relevant atomic data calculated with Flexible Atomic Code allowed us to determine the space-charge correction due to the electron beam including the neutralization factor by the ion cloud of the EBIT.

We report measurements and identification of the E3 4f7/2,5/2-5s1/2 transitions and E1 allowed transitions in Ag-like W (Z = 74), Re (Z = 75), and Ir (Z = 77). The spectra were recorded at the NIST EBIT using a grazing-incidence EUV spectrometer. The present measured wavelengths and theoretical predictions using GRASP2K calculations confirm previous observations of the same E3 transitions in Ag-like W. Our collisional–radiative model using the NOMAD code offers an insight into the population kinematics for Ag-like ions of heavy elements. We discuss the observed spectra and comparisons of the measured and simulated spectral lines.

Extreme ultraviolet spectra of Na-like and Mg-like Os and Ir were recorded at the National Institute of Standards and Technology using a grazing incidence spectrometer. We report a method in EBIT spectral analysis that reduces signals from contaminant lines of known or unknown origin. We utilize similar ion charge distributions of heavy highly charged ions that create similar potentials for lighter contaminating background elements. First-order approximations to ion distributions are presented to demonstrate differences between impurity elements with and without heavy ions present.