The dynamics of target ionization by fast higly charged projectiles

We report on the first kinematically complete investigation of single target ionization by fast heavy ions, on the measurement of all low energy electrons down to zero emission velocities and on the determination of the projectile energy loss on the level of #DELTA#E_p/E_p#approx#10"-"7. This has been achieved by combining a high-resolution recoil-ion momentum spectrometer with a novel 4#pi# electron analyzer. The complete momentum balance between electron, recoil-ion and projectile for single ionization of helium by 3.6 MeV/u Ni"2"4"+ was explored. Low energy electrons are found to be ejected mainly into the forward direction with a most likely longitudinal energy of only 2 eV. The electron momentum is not balanced, as might be expected, by the projectile momentum but is nearly completely compensated by the recoil ion. Surprisingly, the momenta of the helium-atom ''fragments'', the electron and the He"1"+ recoil ion, are considerably larger than the total momentum loss of the projectile: the target atom seems to dissociate in the strong, longranging projectile potential. The collision has to be considered as a real three body interaction. (orig.)12 refs.Available from TIB Hannover: RO 801(95-85) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman