ATOMIC CHARGE-EXCHANGE BETWEEN FAST HELIUM-IONS AND TARGETS FROM CARBON TO BISMUTH AT BETA=0.36

Equilibrium charge-state distributions for singly and doubly ionized He3 ions of energy E(3He)=200 MeV (=0.36) have been measured for atomic targets ranging from carbon to bismuth (Z=6,14,28,40,50,67,73,83). A magnetic spectrometer was used to simultaneously measure the rate of He+3 ions and the current of the incident beam of He2+3 ions. The ratio of the fraction of ions Y(3He+/Y(3He2+) was found to increase from 3×10-9 for Z=6 to 2×10-7 for Z=83. Very good agreement with the experimental ratios was obtained for calculated ratios based on theoretical stripping (ionization) and capture cross sections. The cross sections are dominated by capture from K orbits only for atoms up to about Z=25. For target atoms with high Z, contributions up to principal quantum numbers n=4 (N orbits) must be included. © 1994 The American Physical Society.