[en] A possibility of studying the solar activity and solar cosmic rays in the past by means of cosmogenic isotopes is considered. Attention is paid to a considerable increase in the accuracy of the radiocarbon method. A revealed correlation between the solar sunspots and the cosmic ray flux makes it possible to study the time history of the latter. Neutron production and the rate of ¹⁴C generation in the Earth atmosphere, the intensity of cosmic rays at minima of solar activity and an increase in the ¹⁴C concentration in the atmosphere of the Earth are discussed. Time characteristics of the exchange reservoir of radiocarbon in the atmosphere of the Earth are considered as a part of the general problem