COMPLETE MOMENTUM BALANCE FOR SINGLE IONIZATION OF HELIUM BY FAST-IONIMPACT - EXPERIMENT

The collision dynamics of He single ionization by 3.6 MeV/u Se28+ impa ct was explored using the reaction microscope of the Gesellschaft fur Schwerionenforschung, a high-resolution integrated multielectron recoi l-ion momentum spectrometer. The complete three-particle final-state m omentum distribution (nine Cartesian components p(i)) was imaged with a resolution of Delta p(i) approximate to +/-0.1 a.u. by measuring the three momentum components of the emitted electron and the recoiling t arget ion in coincidence. The projectile energy loss has been determin ed on a level of Delta E-p/E-p approximate to 10(-7) and projectile sc attering angles as small as Delta theta approximate to 10(-7) rad beca me accessible. The experimental data which are compared with results o f classical trajectory Monte Carlo calculations reveal an unprecedente d insight into the details of the electron emission and the collision dynamics for ionization of helium by fast heavy-ion impact.