Fully Differential Single Ionization Cross Sections of Helium by Relativistic Heavy-Ion Impact

We present three-dimensional images of fully differential cross sections for ionization of He by 1 GeV/amu U92+ impact. This collision system corresponds to a relatively large perturbation (projectile charge to velocity ratio η = 0.8) in spite of a relativistic projectile speed of 90% speed of light, representing a kinematic regime which so far is to a large extent still unexplored. Here, in spite of the large perturbation, higher-order contributions in the projectile–electron interaction are very small, but at the same time we find the projectile–residual target-ion interaction to be quite important