Laboratory Measurements and Identification of the Fe XVIII-XXIV L-Shell X-Ray Line Emission

Abstract

A comprehensive survey of Δn ≥ 1 iron L-shell X-ray line emission is presented. We have used the electron beam ion trap EBIT-II at the Lawrence Livermore National Laboratory and equipped with flat crystal spectrometers to measure the wavelengths of over 150 features between 10.6 and 18 Å. We present wavelengths, line identifications, and relative intensities of all of the significant Δn ≥ 1 L-shell line emission from Fe XVIII-XXIV at electron densities of ∼1012 cm-3 resulting from direct electron impact excitation from the ground state followed by radiative cascades. This data set includes 2-3 times as many lines as are found in current standard line lists.