A SYSTEMATIC STUDY OF (N, BE-7) REACTIONS ON MEDIUM AND HEAVY MASS NUCLEI INDUCED BY 53 MEV D(BE)-BREAKUP NEUTRONS

Cross sections were measured radiochemically for the first time for (n , Be-7) reactions on Al, Si, V, Fe, Co, As, Nb, Au and Bi induced by 5 3 MeV d(Be)-breakup neutrons. The values range between 0.2 and 4.5 mub . The cross sections show a slightly decreasing trend with the increas ing asymmetry parameter (N-Z)/A of the target nucleus. Of all the ligh t complex particles (H-2, H-3, He-3, He-4, He-6, Be-7 etc.) observed i n breakup neutron induced reactions, Be-7 emission constitutes the wea kest reaction channel. Obviously, except for He-4, the higher the mass of the emitted complex particle, the lower is its emission probabilit y. The SUM of He-3 and He-4 emission cross sections is by about three orders of magnitude higher than that for the emission of a Be-7 articl e.