Spectroscopy of $2s_{1/2}-2p_{3/2}$ transitions in ${\text{W}}^{65+}$ through ${\text{W}}^{71+}$

A high-resolution flat-crystal spectrometer was used on the SuperEBIT electron beam ion trap to measure the energies of the $2s_{1/2}-2p_{3/2}$ transitions in lithiumlike through fluorinelike tungsten. These transitions are strongly affected by energy shifts due to quantum electrodynamics (QED). SuperEBIT was run at an electron energy of $103.2\pm 0.5\text{keV}$ and an electron beam current of 150 mA to generate the respective charge states; hydrogenlike aluminum and neonlike krypton were used as calibration elements. The spectra were analyzed with and the results compared to calculations based on the flexible atomic code. Good agreement was found. The measurements yielded line positions with a precision of 1–2 eV, which test QED calculations to 5%–10%.

Figure 1

Spectrum of tungsten from SuperEBIT recorded with the EBIT calorimeter spectrometer (ECS). Transitions between levels of principal quantum number $n$ are labeled.

Figure 2

Spectrum of hydrogenlike aluminum recorded on SuperEBIT with the flat-crystal spectrometer. Additional lines from heliumlike silicon are marked as well. These lines are used for wavelength calibrations.

Figure 3

Spectrum of neonlike krypton recorded on SuperEBIT with the flat-crystal spectrometer. Unlabeled lines are mostly from fluorinelike krypton. The neonlike krypton lines are used for wavelength calibrations.

Figure 4

Spectrum of the $2_{1/2}-2p_{3/2}$ transitions of tungsten recorded on SuperEBIT with the flat-crystal spectrometer. The lines are labeled using the isoelectronic notation from Table .