Measurements of charge transfer and4He2+production in collisions between protons and4He+ions

A coincidence technique has been developed and used to measure the cross sections for charge transfer between protons and 4He+ ions at centre-of-mass energies between 14 and 67 keV. In addition, the range of the authors' previous measurements of cross sections for 4He2+ production was extended to 67 keV. Below 14 keV the molecular state calculations of Winter et al. (1980) and Kimuran and Thorson (1981) agree closely with the measurements and, throughout the whole energy range, the recent calculations by Fritsch and Lin (1982) and Winter (1982) are on average, about 15% larger than the authors' results. The absolute accuracy of the measurements is assessed to be +or-12%.