Fragmentation of 370MeV/n 20Ne and 470MeV/n 24Mg in light targets

Abstract

Total charge-changing cross sections and cross sections for the production of projectile-like fragments were determined for fragmentation reactions induced by 370 MeV/n Ne-20 ions in water and lucite, and 490 MeV/n Mg-24 ions in polyethylene, carbon and aluminum targets sandwiched with CR-39 plastic nuclear track detectors. An automated microscope system and a track-to-track matching algorithm were used to count and recognize the primary and secondary particles. The measured cross sections were then compared with published cross sections and predictions of different models. Two models and the three-dimensional Monte Carlo Particle Heavy Ion Transport Code System (PHITS) were used to calculate total charge-changing cross sections. Both models agreed within a few percent for the system Mg-24 + CH2, however a deviation up to 20% was observed for the systems Ne-20 + H2O and C5H8O2, when using one of the models. For all the studied systems, PHITS systematically underestimated the total charge-changing cross section. It was also found that the partial fragmentation cross sections for Mg-24 + CH2 measured in present and earlier works deviated up to 20% for Z = 6-11. Measured cross sections for the production of fragments (Z = 4-9) for Ne-20 + H2O and C5H8O2 were compared with predictions of three different semi-empirical models and JQMD which is used in the PHITS code. The calculated cross sections differed from the measured data by 10-90% depending on which fragment and charge was studied, and which model was used. (C) 2010 Elsevier Ltd. All rights reserved.