COULOMB EXPLOSION OF 173-MEV HEH+ IONS TRAVERSING CARBON FOILS

The Coulomb explosion of 173-MeV HeH+ molecular ions traversing thin c arbon foils has been measured for foil thicknesses ranging from 2 to 2 00 mu g/cm(2). In contrast with measurements al lower Energies, the en ergy spectra for protons observed emerging in the incident beam direct ion show distinct components that correspond to the partner helium ion s being in charge states 0, 1, and 2. From an analysis of the variatio n of tile yields of these components as functions of the target thickn ess, we extract electron-loss cross sections that are in good agreemen t with theoretical estimates. ''Wake effects'' that increase with incr easing target thickness ate observed as asymmetries in the yields and energy shifts for ''backward-going'' as compared to ''forward-going'' protons.