Nuclear fragmentation cross section measurements for a 400 MeV/nucleon O 16 beam on polyethylene and hydrogen targets with the FOOT experiment

The measurement of fragmentation cross sections for nuclei up to Fe 56 on light elements found in the human body (e.g., H, C, and O) is of fundamental importance for particle therapy (PT) and radioprotection in space (RPS), as well as for advancing cosmic-ray physics. These measurements can significantly improve the accuracy of dose calculations for patients during PT treatments and for astronauts exposed to cosmic radiation during deep-space missions. Among the many ions of interest, O 16 is used in PT and is the most abundant species within the HZE component of cosmic rays. This paper presents the results of angular nuclear fragmentation cross sections for the production of He, Li, Be, B, C, and N nuclei in the interaction of a 400 MeV / nucleon O 16 beam with a hydrogen and polyethylene target. The fragmentation on the hydrogen was measured by combining the results on polyethylene with recent measurements on a graphite target. While the fragmentation on hydrogen is fundamental for improving nuclear interaction models, allowing more accurate predictions of dose distributions in PT and RPS, polyethylene has proven to be a promising shielding material in radiation protection models. The data analyzed were collected in 2021 at the GSI Helmholtz Center for Heavy Ion Research facility in Darmstadt (Germany) by the FOOT Collaboration. All results were compared with different Monte Carlo models for light ion fragmentation physics in the energy range of interest implemented in FLUKA and Geant4.