Identification of Nilsson Orbitals in the Superdeformed Minimum of 237Pu
As the first case ever studied with high - resolution \n spectroscopy for odd-N nuclei in the second potential minimum, the fission isomers in 237Pu (t1/2 = 110ns/1.1 \u03bcs) were investigated using the 235U(alpha,2n)\nreaction with a pulsed alpha beam (Ealpha =24 MeV, Deltat=400 ns) from the Cologne Tandem accelerator. A metallic 235U target (3.7 mg/cm2)was used, where the 237Pu reaction products were stopped and fission products were emitted in opposite directions. The rare \ngamma-rays from\nthe second potential well in delayed coincidence with fission products were measured with the MINIBALL spectrometer. The identified level scheme will be presented and compared to single - particle calculations\nallowing for the first time an identification of the Nilsson quantum numbers. The identification of Nilsson orbitals will provide an important input for the validation and improvement of theoretical nuclear models and will lead to improved predictions for fission barriers and\ntheir extrapolations to neutron-rich heavy elements in the mass region\nof the r-process path of the astrophysical nucleosynthesis.