Analysis of fragmentation excitation functions of lead by carbon ions up to 400 MeV/u

Ogawa, Tatsuhiko   ; Morev, M. N.*; Sato, Tatsuhiko   ; Hashimoto, Shintaro  

Fragmentation reaction cross sections of lead bombarded by carbon ions below 400 MeV/u were measured and compared with those simulated with the Monte Carlo radiation transport code PHITS to pinpoint the problems of simulation based on the quantum molecular dynamics model and statistical decay model. Cross sections for 32 fragments from 24 to 85 amu and those from 121 to 175 amu were measured within a reasonable uncertainty. Comparison shows that production cross sections for fragments from 20 to 60 amu and those from 110 to 130 amu are underestimated by one order of magnitude. Further simulation shows that the production of each group of fragments in the simulation is attributed to evaporation of fission fragments and to evaporation of highly excited prefragments, respectively. The observed underestimation indicates the presence of nuclear reaction mechanisms (not considered in the current simulation), such as multi-fragmentation.