Different types of gamma and electron detectors based on registration
of the electromagnetic (EM) cascades are widely used in the modern HEP
experiments. Thus the properties of EM showers are of particular
interest. In this report the new results on the fluctuations of charge particles fluxes in the EM cascades initiated by 10 to 1000
GeV electrons in lead are presented. GEANT4 was used to calculate showers development in these studies.
It is shown for the first time that asymmetric distributions of
charge particle multiplicities are well described by the inverse sum
of two exponents with 3 free parameters in a wide range of the Pb
thickness where the average particle flux >>1. Two of these
parameters define the steepness of the distribution slopes and the
third one is close to the most probable value. The dependence of the
distribution shapes on the shower depth is discussed in details.
Presented data allow one to calculate the multiplicity distribution
for any Pb depth and shower energy within the studied intervals.