Tungsten spectroscopy in the EUV range observed at a high-temperature superconducting electron-beam ion trap

Abstract

We have recorded extreme ultraviolet spectra from ${\mathrm{W}}^{11+}$ to ${\mathrm{W}}^{15+}$ ions using a flat-field spectrometer installed at the Shanghai high-temperature superconducting electron-beam ion trap. The spectra were recorded at beam energies ranging between 200 and 400 eV and showed spectral lines and transition arrays in the 170--260 \AA{} region. The charge states and spectra transitions were identified by comparison with calculations using a detailed relativistic configuration interaction method and collisional-radiative model, both incorporated in the flexible atomic code. Atomic structure calculations showed that the dominant emission arises from $5d$ $\ensuremath{\rightarrow}$ $5p$ and $5p$ $\ensuremath{\rightarrow}$ $5s$ transitions. The work also identified the ground-state configuration of ${W}^{13+}$ as $4{f}^{13}5{s}^{2}$ both theoretically and experimentally.