First observation of isomeric transition from 148m Pr and parity assignment for excited levels in 148Pr
Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 739-8527, Higashi-Hiroshima, Japan
2 Research Reactor Institute, Kyoto University, 590-0494, Kumatori, Japan
3 Facility for Nuclear Materials, Nagoya University, 464-8603, Nagoya, Japan
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Internal conversion electrons from the decay of 148Ce and 148mPr have been measured with a Si(Li) detector. The radioactive sources were produced by the thermal neutron-induced fission of 235U, followed by an on-line mass separation. K- and L-conversion electrons of the isomeric transition from 148mPr were newly observed at 34.6 and 70.8 keV, respectively. The M3 multipolarity was assigned to this transition from the experimental conversion coefficients, and, consequently, the 76.8 keV isomeric level was found to be a 4- state. Parities of some excited levels in 148Pr were also deduced.
© Società Italiana di Fisica and Springer-Verlag, 2004