• nuclear reaction
• nucleon removal
• radioactive nuclei

This thesis is concerned with a systematic theoretical analysis of neutron knockout reactions of exotic nuclei that have large differences in valence neutron and proton separation energies.
A large set of published data already exists in the literature.
The data consist of absolute cross sections for one-nucleon knockout as well as inclusive parallel momentum distributions of the residual nucleus.
They have been collected by various experimental groups in order to deduce information on the structure of the nuclei, in particular of their valence nucleons because this kind of reaction is so peripheral that only the particles on the surface of the nucleus are involved.
The absolute value of the cross section is proportional to the occupancy number (spectroscopic factor) of the initial bound state of the nucleon while the shape of the momentum distribution is related to the angular momentum of the removed particle.
Some anomalies have been found in comparing the experimental results to the theoretical analyses, which used structure model such as the shell model and the eikonal reaction model.
The two main anomalies were an apparent reduction in the occupancy of the deeply bound nucleons and deformed momentum distributions as compared as those from the eikonal model.
In order to understand and, if possible, clarify the origin of such anomalies, we will discuss in this work an alternative reaction model, and when possible, use also a different structure model.
We shall compare our calculations to data already present in the literature and also apply them to new unpublished data that involve light nuclei.
The plan of this work is as follows.
First a brief introduction of the nuclear properties is given to outline the fundamental differences between stable and exotic nuclei.
The radioactive ion beam production mechanisms are described to understand better the difficulties associated to the reactions which involve these short-living nuclides.
We then introduce the formalism of the transfer-to-the-continuum model from which we will obtain our theoretical knockout cross sections.
The formalism contains two parts: one deals with the valence neutron breakup from the projectile, the other accounts for the probability that the projectile residual nucleus (called the core) survives the interaction with the target.
The fact that the core survives intact is fundamental in the knockout experiments because the residue is the detected product of an inclusive reaction.
The ingredients necessary to describe the neutron breakup are: the initial neutron wave function and the neutron-target (9Be) interaction, which is properly described by the optical model scattering matrices developed to reproduce the n+9Be scattering data.
We have performed the calculations with two different scattering matrices from two optical potentials in order to quantify the sensitivity of the cross section.
On the other hand the core survival probability is described by a S-matrix to which a correction is introduced in order to take into account the fact that the valence proton is not knocked out from the projectile even if in some cases it is much less bound than the valence neutron.
The comparison between the experimental differential cross section distribution and the calculated distribution from our model will be presented as well as their integrated values.
To deduce further information on the structure of the lightest nuclei, valence nucleon wave functions from Variational MonteCarlo model will be used, in addiction to the standard shell-model wave functions calculated in a Woods-Saxon potential.
Our results seem to indicate that the anomalies can be explained in terms of a more suitable and accurate reaction theory which takes into account kinematics as well as other single-particle initial states available for the valence nucleons.
The strong absorption radius, the most important parameter to describe the core-target scattering, also seems to play a fundamental role in determining the absolute value of the inclusive knockout cross section.