in the (y,P 0 ) 8,12 and (y, n 0 ) 14 angular distributions suggests that this E2 radiation is mainly isovector. Thus, there is evidence for an energy splitting between the isoscalar and isovector E2strength distributions.Of course the details of the above conclusions depend upon our estimate of the contribution to the strength from other particle channels. It will be important to have data from other reactions in order to complete the empirical determination of the 2s2-strength distribution-Further details of this work, including the El resonances and their bearing on isospin mixing and intermediate structure in the GDR, will soon be published.In order to determine the low-energy neutronneutron scattering parameters a large number of experiments on the reaction n + 2 H -n + n +p were performed during the last years. The method to extract these data was based on comparison of experimental results with theoretical calculations mainly in regions where the n-n final-state interaction (FSI) is dominant; consequently, efforts Weisser, J. Phys. A: Proc. Phys. Soc., London^, L27 (1974). 4 For previous studies of this reaction, see J. D. Larson and R.were made to use a geometry which allows detection of events with small relative kinetic energy of the two neutrons.Since the numerous kinematically incomplete measurements 1 did not give unique results, mainly because of the insensitiveness of the various integrated theoretical differential cross sections to the parameters to be determined, it was nec-The differential cross section of the reaction 2 U(n,np) was measured at 0 n = 0°. Because of the applied special geometry the experimental data extend over a large fraction of the phase space, including several final-state interaction regions as well as regions far from the dominance of the quasi-two-body processes. This offers the possibility of extracting neutron-neutron scattering parameters and obtaining simultaneously additional information on the N-N potentials and three-body forces in the frame of an exact three-body calculation.1063
