  Experimental data on Coulomb breakup and neutron removal indicate that 31Ne
is one of the heaviest halo nuclei discovered so far. The possible ground state
of 31Ne is either 3/2- coming from p-wave halo or 1/2+ from s-wave halo. In
this work, we develop a treatable model to include deformed wave functions and
a dynamical knockout formalism which includes the dependence on the nuclear
orientation to study the neutron removal from 31Ne projectiles at energies
around E=200 MeV/nucleon. A detailed account of the effects of deformation on
cross sections and longitudinal momentum distributions is made. Our numerical
analysis indicates a preference for the 31Ne ground state with spin parity
3/2-.
