The characteristics of the halo neutron preemission in the fusion of 11Li with light targets

The main characteristics of the halo neutron preemission in the fusion of 11Li nuclei with light targets are reviewed. The recent experiment with a new array detector aimed at investigating neutron pair preemission is described. The position distribution measurement confirms the preemission of the halo neutrons in a very narrow forward cone of ∼9 msrad. A novel approach for cross-talk rejection is described. By means of this approach, the true n-n coincidence sample was obtained. In view of obtaining the n-n correlation function, the crucial problem of the denominator construction is thoroughly analyzed. It was found that the single-product denominator built by a random coupling of single detected neutrons followed by cross-talk rejection, exceeds by up to 70% the denominator constructed by the event-mixing technique. We consider this behavior of the single-product denominator together with the large fluctuations seen when represented in small steps of relative momentum q as experimental evidence for residual correlation of single detected halo neutrons