Geochronology and monitoring of cosmic rays for accumulating cosmogenic isotopes Mn-53 and Be-10 in terrestrial rocks

摘要

The paper is devoted to discussing the method of measuring the accumulation of radioactive isotopes Mn-53 (with a half-life T = 3.7 million years) and Be-10 (T = 2.5 million years) in iron-bearing rocks. Knowledge of the dynamics of the accumulation of these isotopes would allow us to estimate the variations in the intensity of cosmic rays, periods of glaciations and geological changes, as well as climatic processes on the Earth in retrospect of 0.1-10 million years. For an operative study of a large number of samples, it has been proposed to use a low-cost neutron activation method with the implementation of the Mn-53(n, gamma)Mn-54 reaction in a slow neutron reactor. As has been shown, using the 10Be isotope together with Mn-53 makes it possible to simultaneously determine both the cosmic-ray fluxes and the shielding time of the corresponding region from cosmic radiation. To obtain the reliable data on cosmic rays, it has been proposed to study rock samples from the lunar surface.