New Beta-delayed Neutron Measurements in the Light-mass Fission Group

A new accurate determination of beta-delayed neutron emission probabilities from nuclei in the low mass region of the light fission group has been performed. The measurements were carried out using the BELEN 4π neutron counter at the IGISOL-JYFL mass separator in combination with a Penning trap. The new results significantly improve the uncertainties of neutron emission probabilities for 91Br, 86As, 85As, and 85Ge nuclei.