Lithium and beryllium isotopes in the PAMELA experiment

Using PAMELA flight data for 2006–2014 on the rigidity of detected nuclei and their velocity (time-of-flight analysis and ionization losses in the multilayer calorimeter of the device), a new analysis of the isotopic composition of Li and Be nuclei in the rigidity range 1–5 GV (nuclear energies 0.1–1.5 GeV/nucleon) was carried out. The new PAMELA data expand the energy range of previous measurements, are consistent with the few existing measurements, and indicate correlated deviations of Li and Be isotope ratios from the GALPROP data for GCRs, which can be interpreted as evidence of the observation of contributions from several nearby local sources against the GCR background. The analysis of precision AMS-02 data on the spectra of positrons, antiprotons, secondary nuclei Li, Be, and B, also carried out in this work, indicates correlated increases in intensity at rigidities of ~50–1000 GV, which could be associated with local sources as well. We estimate the contribution of local sources against the GCR background at the level of tens of percent for rigidities of 1–5 GV and at the level of a few percent for rigidities of 50–1000 GV.