Crossed-beam coincidence studies of ionisation and electron capture in collisions of multiply charged ions with hydrogen atoms

The authors present further measurements of cross sections for ionisation of atomic hydrogen using a crossed-beam coincidence technique previously developed in this laboratory. Cross sections for ionisation by 400-9756 keV Ar (3-9)+ and 1000-4770 keV C (2-6)+ and O (2-6)+ ions have been determined and considered in terms of cross section scaling predictions. The authors have adapted the experimental technique to permit studies of one-electron capture by multiply charged ions; previous measurements have relied entirely on the furnace target method. The effectiveness of this alternative approach has been demonstrated by measurements of the cross section for electron capture by 140-4000 keV Ar (3-6)+ ions. The cross sections for the combined processes of charge transfer and ionisation have been considered in terms of classical scaling rules.