The influence of non-parallelism of electron and positron velocities upon high-energy e+e− pair ionization loss in thin plate

The problem of high-energy electron-positron pair ionization loss in thin plate is considered. It is shown that in this case the approximation of parallel electron and positron velocities which is usually used for calculation of pair ionization loss may not be strictly valid and the existence of non-zero angle of pair divergence can lead to slight suppression of the Chudakov effect of pair ionization loss reduction. The conditions under which such suppression has noticeable value are discussed.