Single neutron emission following 11Li β-decay

The spectrum of neutrons emitted after the β-decay of ¹¹Li has been measured with a large time-of-flight array. The spectrum exhibits six peaks corresponding to neutron emission from known states in the ¹¹Be daughter nucleus. The measured branching ratios indicate significant feeding to states over a broad energy range. The energies and parities of the states are in very good agreement with the previous results of the ⁹Be(t,p) reaction. Comparison of the present results with shell model calculations indicate the effect of the two neutron halo in ¹¹Li. The beta-delayed neutron spectrum of ⁸He was determined in order to remove contributions from beam contamination.