New measurement of the elemental fragmentation cross sections of 218 MeV/nucleon <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Si</mml:mi><mml:mprescripts/><mml:none/><mml:mn>28</mml:mn></mml:mmultiscripts></mml:math> on a carbon target
Guang-Shuai Li, Jun Su, B. Sun, Satoru Terashima, J. Zhao, Xiao-Dong Xu, Jichao Zhang, Ge Guo, Liuchun He, Weiping Lin, Wen-Jian Lin, Chuan-Ye Liu, Chen-Gui Lu, B. Mei, Zhiyu Sun, I. Tanihata, Meng Wang, Feng Wang, Shitao Wang, Xiu-Lin Wei, Jing Wang, Jun-Yao Xu, Jinrong Liu, Mei-Xue Zhang, Yong Zheng, Li-Hua Zhu, Xueheng Zhang
Abstract
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 $^{28}\mathrm{Si}$ 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 $\mathrm{\ensuremath{\Delta}}Z=1\ensuremath{-}6$ are compared to the previous measurements and to the predictions from the models modified EPAX2, EPAX3, FRACS, ABRABLA07, NUCFRG2, and IQMD coupled with GEMINI ($\mathrm{IQMD}+\mathrm{GEMINI}$). All the models fail to describe the odd-even staggering strength in the elemental distribution, with the exception of the $\mathrm{IQMD}+\mathrm{GEMINI}$ model, which can reproduce the EFCSs with an accuracy of better than 3.5% for $\mathrm{\ensuremath{\Delta}}Z\ensuremath{\le}5$. The $\mathrm{IQMD}+\mathrm{GEMINI}$ 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.