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On the measurement and interpretation of the fluxes of galactic cosmic-ray nuclei

PhD ceremony:Mr E. (Eduardo) Ferronato Bueno
When:December 06, 2022
Start:14:30
Supervisor:prof. dr. A.M. van den Berg
Co-supervisors:M. (Manuela) Vecchi, PhD, dr. F. Barao
Where:Academy building RUG
Faculty:Science and Engineering

Since their discovery at the beginning of the last century, the study of cosmic rays (CR) has been the source of important discoveries about how our Universe works. Still, the origins of such particles and the processes that govern their propagation in our Galaxy are open questions. In recent times, experiments such as the Alpha Magnetic Spectrometer (AMS-02), a particle physics detector operating aboard the International Space Station since May 2011, have brought us to a precision era in studying these particles. The data provided by AMS-02 has allowed for the study of CR propagation processes and their origin and acceleration mechanisms. This thesis is divided into two parts. The first is dedicated to the phenomenological interpretation of the published AMS-02 data of nuclei with atomic numbers greater than two, carefully considering the uncertainties in the relevant nuclear cross sections. The results indicate that a simple diffusion model can reproduce the fluxes of all secondary species measured by AMS-02 with atomic numbers between 2 and 9. The second part was devoted to measuring the flux of CR deuterons, the most abundant secondary species in CRs. Several methods were developed for the different stages of the analysis: a multivariate method for background reduction, a parametric template fit for identifying particles, and an unfolding method for the deconvolution of the measured spectrum from instrumental effects. The measured deuteron flux covers the range between 0.2 and 10 GeV/n with unprecedented accuracy, providing the first ever data between 4 and 10 GeV/n.