ANGULAR DIFFERENTIAL CROSS-SECTION MEASUREMENTS IN LIGHT ION-ION COLLISION SYSTEMS

Scattering distributions for charge exchange both in H+ + H+ collision s, the simplest ion-ion collision system, and He+ + He+ collisions hav e been measured at cm-energies between 5 and 16.5 keV. For the measure ments, we have employed a crossed-beams technique and position sensiti ve detection of the neutral reaction products. In contrast to heavy co llision systems, the observed cm-scattering angles are small (theta(cm ) much less than 1 degrees), so the primary ion beam profile as well a s the transformation between lab- and cm-system has to be taken into a ccount when extracting angular differential cross sections from the sc attering distributions.