First dielectronic recombination measurements with H-like uranium

Abstract In this report we show first results on dielectronic recombination (DR) measurements with H-like uranium U 91 + . 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 U 91 + this novel technique enabled us to measure for the first time the KLL-DR process and even to resolve the individual j – j ′ fine structure components of the KL j L j ′ resonances. The experimental data are compared with fully relativistic Multi-Configuration Dirac-Fock (DR-MCDF) calculations.