Observation of Large Scissors Resonance Strength in Actinides
Abstract
The orbital M1 scissors resonance has been measured for the first time in the quasicontinuum of actinides. Particle-γ coincidences are recorded with deuteron and 3He-induced reactions on 232Th. The residual nuclei 231,232,233Th and 232,233 Pa show an unexpectedly strong integrated strength of BM1=11-15μn2 in the Eγ=1.0-3.5 MeV region. The increased γ-decay probability in actinides due to scissors resonance is important for cross-section calculations for future fuel cycles of fast nuclear reactors and may also have an impact on stellar nucleosynthesis.