Spectroscopy of Very Neutron-Rich Nuclei
At PN1, fission products are neutron rich. Many of them are situated about 6 to 10 neutrons away from the line of stability, and are located near to the astrophysical r-process path or even approach in selected cases the neutron drip line.
It is speculated that very neutron-rich nuclei possess, for heavier species, a neutron skin. The increased neutron density at the nuclear surface is thought to be the origin of new phenomena such as modifications or even the disappearance of well known shell gaps.
These phenomena are best tracked down by spectroscopic investigations. During recent years nuclei around the doubly magic 132Sn were investigated at PN1; in particular, the energies, lifetimes and decay modes of microsecond isomers were studied.
The figure gives a systematic survey of the microsecond isomers in odd-Sn isotopes.