On leaky-box approximation to GALPROP

The Galactic Propagation (GALPROP) numerical code is now accepted as an advanced tool for simulations of cosmic-ray diffusion and interaction in the Galaxy. The code is used for the interpretation of a large body of cosmic-ray data. In some cases, including in particular the case of stable primary and secondary nuclei, one can use a simple leaky-box model for handling of data on cosmic-ray energy spectra and composition. We find an adequate leaky-box approximation to the basic GALPROP model and estimate its accuracy.