Recombination of bare Cl17+ ions in an electron cooler

Using an electron beam merged with an energetic ion beam in a storage ring, non-resonant recombination between multiply charged ions and free electron s is studied by measuring directly the rate of recombination products leavi ng the interaction zone. The relative electron-ion energy was varied from m eV energies up to similar to 50 eV. Above similar to 0.5 eV the measured ra tes are well represented by the calculated RR into final states up to the e xperimental Rydberg-ion detection limit. Between similar to 0.01 and 0.5 eV the calculated RR rates are 10% experimental data. As the relative energy is decreased below 0.01 eV the observed recombination rates rise strongly ( to less than or similar to 2.2 times the predicted RR rate), reproducing th e low-energy recombination enhancement found in other recent experiments.