Enhancement of electromagnetic showers initiated by ultrarelativistic electrons in aligned thick germanium crystals

The distribution of the energy deposited in thin silicon detectors placed on the downstream side of a thick germanium single crystal bombarded with a 70, 150 and 250 GeV electron beam along directions close to the 〈110〉 axis or {110} and {100} planes has been measured. The enhancement of the shower with respect to random incidence, as reflected in the higher value of the centroid of the distribution, is studied as a function of the incidence angle to the axis or plane.