Recent results and future prospects for nuclear structure studies at the ILL

摘要

The Lohengrin fission-product spectrometer at the ILL offers some unique opportunities to study the structure of very rare neutron-rich nuclei near Sn-132, in the mass A similar to 100 region and in the A similar to 160 region using microsecond isomeric gamma rays. Techniques to measure isomeric gamma rays, conversion electrons, excited-state lifetimes in the pico-to-nanosecond domain and g factors will be presented. New results on an isomeric state in Zr-98 will also be discussed. A 2.5 mu s isomeric 17(-) state at 6.5 MeV has recently been measured with the Lohengrin spectrometer in Zr-98. This spherical isomeric state is believed to have a (pi (p(1/2)(-2) g(9/2)(2)) v (g(7/2)(1) h(11/2)(1)))17(-) configuration and decays into two collective bands. One of the collective bands has a vibrational character, which becomes rotational at higher spins. An idea to build a neutron guide for nuclear structure experiments on very neutron-rich nuclei at the ILL is currently being discussed. A brief outline of a recent neutron-guide experiment will be presented.