SPECTROSCOPY OF SUPERDEFORMED Pb ISOTOPES

In the mass region around A = 190 about 70 superdeformed (SD) rotational bands are known in 25 different nuclei [1]. In many cases several bands have been found which are built on excited states in the SD potential energy minimum. The nature of these excitations has been the subject of experimental and theoretical investigations in recent years. In the odd-even and odd-odd nuclei it seems clear that the low-lying states are quasiparticle excitations. However, in the even-even isotopes the nature of the excited SD bands in this mass region is less clear. In almoust all cases configuration assignments are difficult since the bands are not linked to lower-lying known states. With the large highly-efficient γ-ray coincidence spectrometers GAMMASPHERE [2] and EUROBALL [3], it is possible to perform a detailed spectroscopy of SD nuclei and to collect sufficient experimental evidence to make reliable configuration assignments. In this contribution, two such investigations of Pb isotopes are selected as examples, the odd-A nucleus 193Pb [4] and the even-even nucleus 196Pb [5]. In 193Pb a total of nine