Measurement of the Production of Boron from the Fragmentation of Cosmic Ray Carbon with NA61/SHINE

This thesis discusses the measurement of the production cross sections of nuclear fragments in carbon-proton interactions at $13.5A$ $\textrm{GeV}/c$ momentum, using data from a pilot run conducted in 2018 at the NA61/SHINE facility at CERN. Cross section measurements with improved uncertainties are key inputs for accurately predicting secondary-to-primary cosmic ray flux ratios, and determining their propagation characteristics in the Galaxy. In this study, the mass-changing, charge-changing, and isotope production cross sections of the $^{11}$B, $^{10}$B, and $^{11}$C nuclei from fragmentation of $^{12}$C have been measured. Two targets, namely polyethylene and graphite, are used to derive the cross section on protons. The primary outcome is the total boron production cross section on the proton target $\sigma^\mathrm{tot. B} = (77\pm5)\,$mb. It aligns closely with previous studies and theoretical predictions achieving a significant reduction in the measured uncertainty compared to prior measurements. Furthermore, this thesis validates the feasibility of measuring low mass fragments at NA61/SHINE. The recent hardware upgrade of the detector electronics have enhanced data acquisition rates. ... mehrWith these improvements and the analysis techniques developed in this thesis, a future high-statistics data taking with NA61/SHINE will be able to provide the precise cross sections needed to exploit the full potential of the recent data from space-based cosmic ray experiments.