Measurement and QRPA calculation of the β-delayed neutron emission of 21,22N and 23,24O☆

Abstract Neutron-rich isotopes of nitrogen and oxygen have been produced as projectile-like fragments in the reaction of a 44 MeV/u 48 Ca beam with a 173mg/cm 2 181 Ta target. The fragments have been analyzed by the doubly achromatic spectrometer LISE and implanted in a semiconductor identification telescope, surrounded by a 4π neutron detector in order to observe their radioactive decay. The β-delayed neutron emission has been measured for the isotopes 21,22 N and 23,24 O for the first time and the β-half-lives T 1 2 and delayed neutron-emission probabilities P n are determined. These values are discussed within the framework of a QRPA calculation. The influence of the decay energy Q β used in the calculation is examined, indicating the reliability of predicted matrix elements. Furthermore, P n values are calculated and compared to the experimental data.