  The 11Be break-up is calculated using a non perturbative time-dependent
quantum calculation. The evolution of the neutron halo wave function shows an
emission of neutron at large angles for grazing impact parameters and at
forward angles for large impact parameters. The neutron angular distribution is
deduced for the different targets and compared to experimental data. We
emphasize the diversity of diffraction mechanisms, in particular we discuss the
interplay of the nuclear effects such as the towing mode and the Coulomb
break-up. A good agreement is found with experimental data.
