Nuclear Seminar

Structural Studies of the Most Exotic Nuclei: First Results from the Stopped RISING Project

Dr. Paddy Regan
University of Surrey

Monday, February 26, 2007   4:00 p.m.   NSH 124
(Refreshments served prior to seminar in NSH 124)

 

Projectile fragmentation reactions at relativistic energies allow unprecedented experimental access to nuclei with the most extreme values of proton-to-neutron ratio.  The RISING (Rare Isotope Spectroscopic Investigations at GSI) project couples the fragmentation production mechanism with high-resolution gamma-ray spectroscopy for the study of internal structure of nature’s most exotic nuclear species.  This talk will present the first experimental results from the RISING gamma-ray array in its ‘Stopped Beam’ configuration, which is designed for studies of spectroscopy of exotic nuclei following isomer and beta-delayed decay.  I will specifically present isomer-spectroscopy identifying new metastable states in nuclei associated with proton holes in the ¹³²Sn and ²⁰⁸Pb doubly-magic closed shells pertinent to the r-process path.  These results reveal new physics associated with T=1, 0 proton-neutron pairing competition along the proton drip line for N=Z nuclei and the persistence (or not) of the N=82 and 126 shell closures for large neutron excess.