2012 Data (Information)

Electron-impact-ionization measurements using hyperfine-assisted state preparation of ground-state berylliumlike sulfur: Data

Hahn, Michael; Bernhardt, D.; Grieser, M.; Krantz, C.; Lestinsky, M.; Muller, A.; Novotny, Oldrich; Repnow, R.; Schippers, S.; Wolf, A.; Savin, Daniel Wolf

We have measured electron impact ionization (EII) of the beryllium-like ion S¹²⁺. The use of an isotopically pure A=33 beam of S¹²⁺ ions is established as a method to eliminate all metastable levels, including the extremely long-lived metastable level 2s2p 3 P0, which, for this isotope, decays by hyperfine-induced radiative transitions. The energy dependence and absolute size of the EII cross section were measured from the resulting pure ground-state population at energies from below the threshold at ≈ 652.2 eV up to 3000 eV. These data provide an experimental benchmark for theory.