First dielectronic recombination measurements with H-like uranium

In this report we show first results on dielectronic recombination (DR) measurements with H-like uranium U91+U91+. The experiments were conducted at the heavy ion storage ring ESR of GSI. The electron cooler of the ESR was used as a target for free electrons. Stochastic pre-cooling of the stored ion beam was employed in order to accomplish high-energy resolution at the necessary high electron–ion collision energies of more than 64 keV. For the DR of U91+U91+ this novel technique enabled us to measure for the first time the KLL-DR process and even to resolve the individual jj–j′j′ fine structure components of the KLjLj′KLjLj′ resonances. The experimental data are compared with fully relativistic Multi-Configuration Dirac-Fock (DR-MCDF) calculations.