Study of light-nuclei in cosmic rays with the PAMELA experiment: Preliminary results

— An important issue for the long-duration satellite mission PAMELA, in orbit from June 2006, is the determination of fluxes and secondary-to-primary ratios for nuclei up to oxygen in the energy range 200MeV/n–150GeV/n. The study of the light-nuclei component of the cosmic radiation is strictly connected to a better understanding of the propagation properties, which has great importance for the study of signatures of new physics in CRs. In particular, cosmic rays of primary origin such as carbon and oxygen may interact with the interstellar medium to produce secondary spallogenic fragments such as lithium, beryllium and boron. The measured ratio of secondary-to-primary cosmic rays can be used to compute the mean amount of interstellar matter that cosmic rays have encountered before reaching the Earth; moreover, the shape of this ratios as a function of energy is seriously modified by changes in the propagation coefficients. Some results about the observation capability of the instrument for nuclei and a preliminary estimation of secondary-to-primary ratios will be presented in this work.