Using the SuperEBIT electron beam ion trap, we have measured the $2s_{1/2}\mathrm{\text{−}}2p_{1/2}$ transitions in ${\mathrm{U}}^{88+}$ and ${\mathrm{U}}^{89+}$. The measured value of $280.645\pm 0.015\mathrm{eV}$ for Li-like ${\mathrm{U}}^{89+}$ improves the available precision by nearly an order of magnitude and establishes a new benchmark for testing the total QED contribution to the transition energy within a fractional accuracy of $3.6\times {10}^{-4}$. We infer a value for the $2s$ two-loop Lamb shift in ${\mathrm{U}}^{89+}$ of $-0.23\mathrm{eV}$, from which we estimate a value of $-1.27\mathrm{eV}$ for the $1s$ two-loop Lamb shift in ${\mathrm{U}}^{91+}$.

The hyperfine splitting of the $1s$ ground state of hydrogenlike Tl has been measured for the two stable isotopes using emission spectroscopy in the SuperEBIT electron-beam ion trap, giving $3858.22\pm 0.30\hspace{0.5em}\AA$ for ${}^{203}{\mathrm{Tl}}^{80+}$ and $3821.84\pm 0.34\hspace{0.5em}\AA$ for ${}^{205}{\mathrm{Tl}}^{80+}$ with a wavelength difference $\Delta \lambda =36.38\mathrm{}\pm 0.35\hspace{0.5em}\AA .$ This difference is consistent with estimates based on hyperfine anomaly data for neutral Tl only if finite size effects are included in the calculation. By using previously determined nuclear magnetic moments, and applying appropriate corrections for the nuclear charge distribution and radiative effects, the experimental splittings can be interpreted in terms of nuclear magnetization radii $〈r_m^2{〉}^{1/2}=5.83\mathrm{}\left(14\right)\mathrm{}\hspace{0.5em}\mathrm{fm}$ for ${}^{203}\mathrm{Tl}$ and $〈r_m^2{〉}^{1/2}=5.89\mathrm{}\left(14\right)\mathrm{}\hspace{0.5em}\mathrm{fm}$ for ${}^{205}\mathrm{Tl}.$ These values are 10% larger than derived from single-particle nuclear magnetization models, and are slightly larger than the corresponding charge distributions.

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At the Livermore electron-beam ion-trap facility, extreme-ultraviolet spectra of tungsten have been recorded in the wavelength range 40–85 Å. The electron-beam energy was varied systematically to identify the individual spectra of Rb-like W³⁷⁺ to Cu-like W⁴⁵⁺. About 60 spectral features have been identified. PACS Nos.: 32.30Rj, 39.30+w, 31.50+w