  The possibility of antihelium production in interaction of cosmic rays with
the interstellar gas is studied using large-scale Monte Carlo simulations. For
this purpose, an energy-dependent coalescence mechanism developed previously is
extended to estimate the production of light antinuclei
(${}^3\overline{\text{He}}$ and ${}^4\overline{\text{He}}$). The uncertainty in
the coalescence parameter and its effect on the expected antiparticle flux is
also investigated. The simulated background antihelium fluxes are found to be
lower than the fluxes predicted by simplified models using numerical scaling
techniques.
