Independent isomer yield ratio of 90Rb

Abstract The independent isomer yield ratio for 90Rb from thermal neutron fission of 235U has been measured by use of a new technique involving a pulsed reactor and an on-line mass spectrometer facility. The observed isomer yield ratio of 8.7 ± 1.0 is one of the largest ratios measured for a low energy fission process. However, a statistical model analysis shows that the average angular momentum (J = 4.5) deduced from this isomer yield ratio is consistent with average angular momentum for other products from low energy fission.