IMPACT PARAMETER DEPENDENCE OF ELECTRONIC-ENERGY LOSS AND STRAGGLING IN FAST PROTON-ATOM COLLISIONS

The impact parameter dependence of the electronic mean energy loss and energy loss straggling is calculated for fast proton collisions with noble gas atoms. The independent electron model using the Hartree-Slat er potential is used for the description of the atoms. A summation ove r all final atomic states is made explicitly. Results of calculations for Ne, Ar, Kr and Xe atoms are presented and compared with recent exp erimental data by Auth and Winter. Good agreement with experiment is o bserved for the impact parameters b < 1.2 a.u., whereas for larger imp act parameters the calculations underestimate the experimental data.