Coherent effect in ionization loss of relativistic electron ensembles in ultrathin targets

Ionization loss of relativistic electron bunches in ultrathin targets is considered. It is shown that the effect of coherent amplification of ionization loss comparing to Bethe-Bloch result, analogous to such effect in radiation, can take place for sufficiently small bunches with high particle densities. It is demonstrated that such effect can manifest itself for bunch parameters achievable on modern accelerator facilities.