Energy Dependent Abundance of Secondary Nuclei in Cosmic Rays: An Indication of Altitude Dependent Convection above the Galactic Plane?

Based on accurate calculations of abundance of secondary nuclei in low energy cosmic rays we suggest a new parametrization for the energy dependent escape time of energetic particles from the Galaxy. The interpretation of this parametrization is suggested in the frameworks of the diffusion convection model with non monotone dependence of cosmic ray convection velocity as a function of the distance from the galactic plane