The work presents calculations of the neutrino-nuclear reaction cross-sections using the
example of the nucleus 𝐺𝑒'( (𝐺𝑒'( 𝜈, 𝑒 𝐴𝑠'( ). In the structure of the nucleus, not only
discrete, but also continuous states formed due to the collective interaction of nucleons were
distinguished. In particular, the contribution of the Giant Gamow-Teller resonance and so-called
pygmy resonances in the capture rate of solar neutrinos was estimated (an increase of 25% to
50%, depending on the quenching parameter used).
Based on the obtained capture rate, a Monte Carlo simulation of the subsequent beta
decay of the nucleus 𝐴𝑠'( (𝐴𝑠'( → 𝑆𝑒'( + 𝑒2 + 𝜈 + 𝑛𝛾) was carried out for germanium
detectors in the GERDA experiment. Thus, the contribution of the background component due
to solar neutrinos was estimated, which, due to the small cross-sections of neutrino-nuclear
reactions, is practically unremovable, imposing confines on the sensitivity limit of the setup.
A similar assessment can be made for the upcoming LEGEND experiment taking into
account its geometry. Preliminary results suggest that BI of solar neutrinos are 1-2 orders of
magnitude lower than the predicted accuracy of the LEGEND experiment.