Dielectronic and Radiative Recombination of Si- to N-like Tungsten Ions

We have performed x-ray spectroscopic measurements of the dielectronic recombination resonance strength for the LMn (n=3, ..., 10) series of Si-like W60+ to N-like W67+ tungsten ions. Highly charged tungsten ions were produced, stored and excited with the Berlin electron beam ion trap and the emitted radiation was analyzed with a solid state detector. Information on the charge state abundance in the trap was extracted from a fit of the theoretical radiative recombination intensity to measured values. The fit procedure was only feasible when the fine structure, angular momentum of the recombination channels is taken into account. Our measurement of x-rays from n=2-3, 2-4 and higher DR resonance transitions was compared to relativistic calculations of the DR cross sections and rate coefficients calculated with the Hebrew University Lawrence Livermore Atomic Code (HULLAC). The previous theoretical predictions for Ne-like tungsten (W64+) [3] were extended with calculations for ions in adjacent charge states and compare well with the observed DR resonance structure.