Differential projectile energy loss in multiply ionizing collisions

The momentum vectors of the recoil ion and up to three electrons were measured in coincidence with the projectiles which did not change charge state for 3.6 MeV amu-1 Au53+ Ne collisions. New techniques were applied to obtain differential energy-loss spectra for multiple-target ionization as a function of the recoil-ion charge state. A resolution unprecedented for this energy regime was achieved. The data are in good agreement with a classical trajectory Monte Carlo calculation. Our studies represent a first step for a method of modelling stopping powers on a microscopic level and are relevant for plasma applications.