Beta-delayed neutron emission from sup(93-100)Rb to excited states in the residual Sr isotopes

Beta-delayed neutron emission from the precursors 93-100Rb to excited states in the residual nuclei 92-99Sr has been measured by means of γ-ray and neutron spectroscopy. In general, considerable neutron feeding of excited final states is observed. The experimental branching ratios (Psub(n)sup(i)) are compared to predictions from statistical model calculations. it is demonstrated that the main parameter affecting the Psub(n)sup(i)-values is the shape of the β-strength function (Ssub(β)). For several Rb isotopes hindrance, respectively enhancement of neutron branches to specific final states is observed giving evidence for the persistence of intermediate structure of the neutron-emitting states. By the example of 98Rb it is shown that a few integral β-delayed neutron properties may be sufficient to derive first estimates on the real shape of Ssub(β) above the neutron binding energy. This result is of importance for exotic nuclei where detailed spectroscopic investigations are precluded. (orig.)