An investigation of the inelastic and elastic reactions between high- energy neutrons nnd He nuclei was conducted with a cloud chamber filled with He and operating in a pulsed magnetic field of 21,700 gauss. Neutrons produced by bombardment of a 1/2-in. LiD target with 340-Mev protons in the 184-in. synchrocyclotron were collimated and passed through the 22-inch expansion cloud chamber, which was filled with He gas to a total pressure of 89.8 cm Hg. Exclusive of meson-producing reactions, the possible reactions are: Inelastic, He/ sup 4/(n,pn)t, He/sup 4/(n,d)t, He/sup 4/(n,2np)d, He/sup 4/(n, dn)d, He/sup 4/ (n,2n2p) n, He/sup 4/(n, 2n) He/s up 3/; and Elastic, He/sup 4/(n,n)He/sup 4/. The total number of events, for incident neutrons above 160 Mev, was normalized to the interpolated n-He/sup 4/ total cross section at 300 Mev, and absolute cross sections for the various processes were established. Energy and angular distributions of the reaction products were compared with available theoretical predictions and other experiments. A few cases of meson production were noted. (auth)
