Precision Measurements of Neon, Magnesium, and Silicon Flux in Cosmic Rays with the Alpha Magnetic Spectrometer on the International Space Station

Abstract

Precise measurements of primary cosmic ray Neon, Magnesium and Silicon flux is important to understand the origins and propagation properties of heavy elements in the Galaxy. This thesis presents the measurements of Neon, Magnesium, and Silicon flux in the rigidity (momentum per unit charge) range from 2.15 GV to 3 TV, with 5.6 million Ne, Mg, and Si nuclei events collected during 7 years of AMS operation (2011- 2018). The three fluxes show identical rigidity dependence above 86.5 GV, deviating from a single power law and hardening at high rigidity above 200 GV. Surprisingly, the rigidity dependence of Neon, Magnesium, and Silicon flux is different from the rigidity dependence of primary nuclei Helium, Carbon and Oxygen, even though the two groups are both primaries produced at cosmic rays sources.