Background: Models describing nuclear fragmentation and fragmentation-fissiondeliver important input for planning nuclear physics experiments and futureradioactive ion beam facilities. These models are usually benchmarked againstdata from stable beam experiments. In the future, two-step fragmentationreactions with exotic nuclei as stepping stones are a promising tool to reachthe most neutron-rich nuclei, creating a need for models to describe also thesereactions. Purpose: We want to extend the presently available data on fragmentationreactions towards the light exotic region on the nuclear chart. Furthermore, wewant to improve the understanding of projectile fragmentation especially forunstable isotopes. Method: We have measured projectile fragments from 10,12-18C and 10-15Bisotopes colliding with a carbon target. These measurements were all performedwithin one experiment, which gives rise to a very consistent dataset. Wecompare our data to model calculations. Results: One-proton removal cross sections with different final neutronnumbers (1pxn) for relativistic 10,12-18C and 10-15B isotopes impinging on acarbon target. Comparing model calculations to the data, we find that EPAX isnot able to describe the data satisfactorily. Using ABRABLA07 on the otherhand, we find that the average excitation energy per abraded nucleon needs tobe decreased from 27 MeV to 8.1 MeV. With that decrease ABRABLA07 describes thedata surprisingly well. Conclusions: Extending the available data towards light unstable nuclei witha consistent set of new data have allowed for a systematic investigation of therole of the excitation energy induced in projectile fragmentation. Moststriking is the apparent mass dependence of the average excitation energy perabraded nucleon. Nevertheless, this parameter, which has been related tofinal-state interactions, requires further study.
展开▼
