We use the three-body model and the sudden approximation to compute an
gular correlations in high-energy fragmentation reactions of two-neutr
on halos an light targets. The contribution from one-neutron absorptio
n by far dominates over that of neutron scattering. We use He-6 (n + n
+ alpha) and Li-11 (n + it + Li-9) as examples and study the dependen
ce of the predictions of this model on different physical assumptions
and parameters. [S0556-2813(98)50111-2].