New neutron magic number N=16 far from stability line

A survey of experimental results obtained at GANIL (Caen, France) resulting in an appearance of a new magic number, N=16, in very neutron-rich nuclei is presented. Recent data on mass measurements of neutron-rich nuclei at GANIL and some characteristics of binding energies in this region are discussed. Nuclear binding energies are very sensitive to the existence of nuclear shells and together with the measurements of instability of the doubly magic nucleus 28O provide new information on changes in neutron shell closures of very neutron-rich isotopes. The behavior of the two-neutron separation energies S2n derived from mass measurements gives a very clear evidence for the existence of the new shell closure N=16 for Z=9 and 10 appearing between 2s1/2 and 1d3/2 orbitals. This fact, strongly supported by the instability of C, N and O isotopes with N>16, confirms the magic character of N=16 for the region from carbon up to neon while the shell closure at N=20 tends to disappear for Z≤13