Neutron-Neutron Correlations in the Dissociation of Halo Nuclei

Revised and updated version of an invited contribution to the RCNP Osaka Spring Workshop on Cluster Condensation and Nucleon Correlations in NucleiStudies attempting to probe the spatial configuration of the valence neutrons in two-neutron halo nuclei using the technique of intensity interferometry are described. Following a brief review of the method and its application to earlier measurements of the breakup of $^{6}$He, $^{11}$Li and $^{14}$Be, the results of the analysis of a high statistics data set for 6He are presented. The limitations of the technique, including the assumption of incoherent emission in the breakup and the sensitivity to the continuum states populated in the dissociation rather than the ground state, are discussed