Delayed neutron emission probabilities of 9Li and 11Li

Abstract The P n values for 9 Li and 11 Li were determined to be (50 ± 4)% and (95 ± 8)%, respectively, by a beta-neutron coincidence technique. The P n values of 27–31 Na, 93–98 Rb and 145–146 Cs, which had been deduced by normalization to the older P n value for 9 Li, should thus be raised by the factor 1.43. The β-decay branch to the 320 keV first excited state of 11 Be was found to be (9.2 ± 0.7)%. The fraction of one-neutron emission leading to excited states of 10 Be was deduced to be (41 ± 4)%. The half-life of 11 Li was remeasured to be (8.83 ± 0.12)ms.