Electron impact single detachment on the F^- ions using the heavy ion storage ring CRYRING: Cross-section determination

Abstract:

Electron Impact Single Detachment (EISD) of F^- has been studied using the heavy ion storage ring CRYRING at the Manne Siegbahn Laboratory, Stockholm, Sweden. F^- ions stored in the ring were merged with an electron beam in one of the ring sections. Neutral F atoms produced in the EISD process were detected in the zero-degree direction using a surface barrier detector. The threshold for the detachment process was found to be around 7.6 eV, thus more than twice the binding energy of F^-. The cross-sections increased smoothly up to 55 eV where it reached a maximum of 1.9×10 ^-16 cm ². At higher energies a slow decrease of the cross-section was observed, which follows the energy dependence predicted by the Bethe-Born approximation. The experiment showed that CRYRING can be used favourably for studies of anions, and several experiments are forthcoming.