Do Be-10 and C-14 give us the information about cosmic rays in the past?

Presenter: I. Nikitin (baai_@mail.ru), rus-nikitin-I-abs1-sh34-oral In the atmosphere cosmic rays produce Be-10, C-14 and other radionuclides. It is commonly supposed that the concentrations of these radionuclides (Be-10 in polar ice and C-14 in tree rings) are good proxies of cosmic ray fluxes impinging on the top of the atmosphere. But before the precipitation on the Earth’s surface these elements spend several years in the atmosphere. The stirring of their concentrations over globe takes place. The analysis of 3 sets of data (2 sets of Be-10 and 1 set of C-14) shows that the correlations between them are low. Also, the relationship between cosmic ray fluxes and Be-10 concentrations in the period of 1937 – 1985 when there are direct cosmic ray flux measurements is weak. It means that the atmospheric processes, which play an essential role in the radionuclide precipitation, can violate the relationship between cosmic ray fluxes and radionuclide concentrations. We suppose that much more reliable is to use the strong relationship of sunspot number with cosmic rays to get cosmic ray fluxes in the past.