Assessing uncertainties in the numerical modelling of cosmogenic radionuclide production.

Abstract

The terrestrial production of cosmogenic radionuclides such as 10Be, 14C and 36Cl is triggered by spallation reactions of high-energy particles with atmospheric constituents such as oxygen, nitrogen and argon. After being produced and transported within the atmosphere, these radionuclides are deposited in natural archives, storing, for example, solar information over thousands of years. Therefore, records of 10Be, 14C and 36Cl can be used to reconstruct solar activity back in time. However, to understand the underlying physical processes that dominate production and interpret the observations, numerical modelling is crucial. Here, we shall discuss the dependencies of the numerically derived production rates on a variety of factors that include the effects of the choice of the local interstellar spectrum (LIS), the geomagnetic field and the production cross-sections available in the literature. We show that the investigated factors have modest to significant impacts on the modelled production rates of cosmogenic radionuclides and identify the discrepancies in the available cross-sections as the most crucial factor. This article is part of the Theo Murphy meeting issue 'Radiocarbon and cosmic radiation events'.