We report on a method to measure charge-changing cross sections for ions passing through matter in nonequilibrium conditions. The charge states of an initial distribution are separated by applying a high voltage before they penetrate thin carbon foils; the charge states after those foils are identified using a high resolution magnetic spectrometer. Thus the full matrix of cross sections $\sigma {(q}_i{,q}_f)$ and energy losses $\Delta {E(q}_i{,q}_f)$ is obtained. The data are compared to calculated charge-state distributions based on microscopic cross sections for charge-changing processes in individual interaction steps and with a Monte Carlo simulation.

• Received 25 August 1999

DOI:https://doi.org/10.1103/PhysRevA.61.032901