Mean Free Paths of He, Li, and Be Produced in Heavy-Ion Collisions at 2 GeV/u

The interaction mean free paths of He fragments emitted from two heavy-ion beams of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ and ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ at energy of 2 GeV/u have been measured with high statistics and were found to be approximately the same at all distances from their production points. Li and Be fragments, produced from known primary beams, also do not show any significant anomalous effect, within the statistics, in their mean-free-path values at any distance from their production point.