  The propagation of cosmic rays in the Earth's atmosphere is simulated.
Calculations of the omnidirectional differential flux of neutrons for different
solar activity levels are presented. The solar activity effect on the
production rate of cosmogenic radiocarbon by the nuclear-interacting and muon
components of cosmic rays in polar ice is studied. It has been obtained that
the $^{14}C$ production rate in ice by the cosmic ray nuclear-interacting
component is lower or higher than the average value by 30% during periods of
solar activity maxima or minima, respectively. Calculations of the altitudinal
dependence of the radiocarbon production rate in ice by the cosmic ray
components are illustrated.
