An updated simulation of particle fluxes and cosmogenic nuclide production in the Earth's atmosphere

Abstract

Since the publication of our first paper devoted to this subject, we have extended our model, using new cosmic ray and nuclear data. Therefore, we revised particle fluxes in the atmosphere and used them in concert with experimental or evaluated cross sections to calculate the production rates of 3 H, 7 Be, 10 Be, 14 C, and 36 Cl. The dependencies of these production rates on solar activity and geomagnetic field intensity were investigated in detail. Our simulations cover a whole range of these two parameters observed in the past. Comparison of the production rates calculated from two of the most frequently used primary galactic cosmic ray spectra showed weak dependence on the shape of the spectra. Alpha particles were included in the simulations for the first time, and we showed that the previously used scheme for estimation of alpha particle contribution to the total production rates is more complicated and latitude dependent. The production rates obtained agree well with most published experimental values. Copyright © 2009 by the American Geophysical Union.