Nuclear spectroscopic studies of neutron-rich nuclei far from stability

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Nuclear spectroscopic studies on neutron-rich fission-produced nuclei have been performed using the on-line isotope separator KUR-ISOL. A new type high-temperature ion source, a large Si(Li) detector and a data aquisition system have been prepared by this grant-in-aid and have effectively been used for the following studies:1) A nwe isotope ^<156>Pm has been discovered among the fission products of ^<235>U. 34 new -ray lines have been assigned to this isotope.2) A new isotope ^<155>Nd has been discovered. The half-life was determined as 9.5 0.7 s and 4 -ray lines have been assigned to this isotope.3) A new isotope ^<154>Pr has recently been discovered with increased beam intensity of KUR-ISOL for rare-earth elements. The half-life is 2.3 0.1 s and 10 new -ray lines have been identified to originate from this isotope.4) Nuclear spectroscopic studies have been performed on the transitional nuclei ^<147>Ba, ^<147>La and ^<147>Ce. Internal conversion electrons and -rays have been precisely measured and a lot of new lines and levels have been identified. The data analyses are now in progress.We are now further improving the ion source and skimmer system to increase the beam intensity of ISOL several times. Further studies on new isotopes and on extremely neutron-rich isotopes will be continued to a deep understanding of nuclear structure of nuclei far from stability.