Deformation of Ne isotopes in the region of the island of inversion

Deformations of Ne isotopes in the island of inversion are determined by the folding model description of the interaction cross sections measured for ^28-32Ne isotopes incident on a ¹²C target at 240 MeV/nucleon, using the Melbourne g-matrix interaction and the nuclear densities calculated by antisymmetrized molecular dynamics (AMD). The double folding model with the AMD density well reproduces the measured interaction cross sections, if the tail correction is made to the AMD density for ³¹Ne. The quadrupole deformation determined is around 0.4 in the island of inversion and ³¹Ne is a halo nucleus with large deformation. We propose the Woods-Saxon model with the AMD deformation and a suitably chosen parametrization set as an approximate but simple method to reproduce the AMD density with the tail correction. The angular momentum projection is essential to obtain the large deformation in the island of inversion. Effects of the pairing correlation are investigated.