Abstract
Background: Models describing nuclear fragmentation and fragmentation
fission deliver important input for planning nuclear physics experiments
and future radioactive ion beam facilities. These models are usually
benchmarked against data from stable beam experiments. In the future,
two-step fragmentation reactions with exotic nuclei as stepping stones
are a promising tool for reaching the most neutron-rich nuclei, creating
a need for models to describe also these reactions.
Purpose: We want to extend the presently available data on fragmentation
reactions towards the light exotic region on the nuclear chart.
Furthermore, we want to improve the understanding of projectile
fragmentation especially for unstable isotopes.
Method: We have measured projectile fragments from (10,12-18C) and
B10-15 isotopes colliding with a carbon target. These measurements were
all performed within one experiment, which gives rise to a very
consistent data set. We compare our data to model calculations.
Results: One-proton removal cross sections with different final neutron
numbers (1 pxn) for relativistic C-10,C-12-18 and B10-15 isotopes
impinging on a carbon target. Comparing model calculations to the data,
we find that the EPAX code is not able to describe the data
satisfactorily. Using ABRABLA07 on the other hand, we find that the
average excitation energy per abraded nucleon needs to be decreased from
27 MeV to 8.1 MeV. With that decrease ABRABLA07 describes the data
surprisingly well.
Conclusions: Extending the available data towards light unstable nuclei
with a consistent set of new data has allowed a systematic investigation
of the role of the excitation energy induced in projectile
fragmentation. Most striking is the apparent mass dependence of the
average excitation energy per abraded nucleon. Nevertheless, this
parameter, which has been related to final-state interactions, requires
further study.
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