NEUTRON-SCATTERING ANGULAR-DISTRIBUTIONS IN PU-239 AT 570 AND 700 KEV

Neutron elastic and inelastic scattering in Pu-239 have been studied v ia the time-of-flight technique. Neutrons were generated by the Li-7(p , n)Be-7 reaction at the University of Massachusetts Lowell 5.5-MV Van de Graaff Accelerator Laboratory. Angular distributions were measured at 570 and 700 keV for two level groups, ground state plus first exci ted state, and second plus third excited state. The plutonium sample w as disk-shaped with a mass of 28.7 g. The angle-integrated cross secti ons obtained for the two scattered neutron groups, one corresponding t o the elastic plus 7.9 keV level and the other corresponding to the in elastic 57 keV plus 76 keV levels, were 5864 +/- 264 mb and 570 +/- 42 mb, respectively, for 570-keV incident neutrons and 5060 +/- 308 mb a nd 518 +/- 62 mb, respectively, for 700-keV incident neutrons. The res ults are compared with ENDF/B-VI and with the measurement of Haouat et al. at 700 keV.