New measurement of the elemental fragmentation cross sections of 218 MeV/nucleon 28Si on a carbon target

Elemental fragmentation cross sections (EFCSs) of stable and unstable nuclides have been investigated with various projectile-target combinations at a wide range of incident energies. These data are critical to constrain and develop the theoretical reaction models and to study the propagation of galactic cosmic rays (GCR). In this work, we present a new EFCS measurement for 28Si on carbon at 218 MeV/nucleon performed at the Heavy Ion Research Facility (HIRFL-CSR) complex in Lanzhou. The impact of the target thickness has been well corrected to derive an accurate EFCS. Our present results with charge changes AZ = 1 - 6 are compared to the previous measurements and to the predictions from the models modified EPAX2, EPAX3, FRACS, ABRABLA07, NUCFRG2, and IQMD coupled with GEMINI (IQMD+GEMINI). All the models fail to describe the odd-even staggering strength in the elemental distribution, with the exception of the IQMD+GEMINI model, which can reproduce the EFCSs with an accuracy of better than 3.5% for AZ 5. The IQMD+GEMINI analysis shows that the odd-even staggering in EFCSs occurs in the sequential statistical decay stage rather than in the initial dynamical collision stage. This offers a reasonable approach to understand the underlying mechanism of fragmentation reactions.

Automated summary

The EFCSs of stable and unstable nuclides were investigated with different projectile-target combinations and a wide range of incident energies. These data are crucial for constraining and developing theoretical reaction models and studying the propagation of galactic cosmic rays (GCR). A new EFCS measurement for 28Si on carbon at 218 MeV/nucleon was performed, and the impact of target thickness was accurately corrected. Comparative analysis of the results with existing measurements and model predictions revealed the limitations of current models in describing odd-even staggering in elemental distribution, except for the IQMD+GEMINI model.