Eiko Takekoshi

Multipolarity of γ-ray Absorption in U238(γ, f) Reaction produced by F(p, αγ) γ rays

Multipolarity of γ-ray absorption in U 238 (γ, f ) reaction, produced by monochromatic γ rays from F( p , αγ) reactions, has been investigated by the analysis of the angular distribution of 1018 tracks of fission fragments in uranium-impregnated nuclear emulsions. It can be explained by mixing two sorts of interaction; electric dipole ( E 1) and electric quadrupole ( E 2). The ratio of E 2 to E 1 absorption cross section, denoted by σ f q /σ f d , has been found to be 0.13±0.05. This value is compared with other results with bremsstrahlung. The angular distribution is consistent with those of Baz et al. , however, the analysis and interpretation of the results are different from those of Baz et al. .

Co59(n, α)Mn56and Mn55(n, α)V52Reactions Induced by 14.8-Mev Neutrons

The angular and energy distributions of alpha particles resulting frora Co/sup 59/(n, alpha )Mn/sup 56/ and Mn/sup 55/(n, alpha )V/sup 52/ reac tions induced by 14.8-Mev neutrons were raeasured with Ilford C2 nuclear plates. As in the case of Al/sup 27/(n, alpha )Na/sup 24/ reaction, the angular distributions for the entire energy region are approximately 90 deg symmetrical and concave upward, and the energy distributions show that the alpha particles with energies below the Couloumb barrier are raore emitted than has been expected. The curves on a semilog plot of the relative level density calculated from the energy distributions of the alpha particles cannot fit a straight line. The total (n, alpha ) cross sections of cohalt end manganese are 84 mb plus or minus 15% and 96 mb plus or minus 15%, respectively. The results are compared with the predictions of the statistical theory of nuclear reactions. (auth)The angular and energy distributions of alpha particles resulting from Co 59 ( n , α)Mn 56 and Mn 55 ( n , α)V 52 reactions induced by 14.8-Mev neutrons were measured with Ilford C2 nuclear plates. As in the case of Al 27 ( n , α)Na 24 reaction, the angular distributions for the entire energy region are approximately 90° symmetrical and concave upward, and the energy distributions show that the alpha particles with energies below the Coulomb barrier are more emitted than has been expected. The curves on a semilog plot of the relative level density calculated from the energy distributions of the alpha particles cannot fit a straight line. The total ( n , α) cross sections of cobalt and manganese are 84 mb±15% and 96 mb±15% respectively. The results are compared with the predictions of the statistical theory of nuclear reactions.

Co

The angular and energy distributions of alpha particles resulting frora Co/sup 59/(n, alpha )Mn/sup 56/ and Mn/sup 55/(n, alpha )V/sup 52/ reac tions induced by 14.8-Mev neutrons were raeasured with Ilford C2 nuclear plates. As in the case of Al/sup 27/(n, alpha )Na/sup 24/ reaction, the angular distributions for the entire energy region are approximately 90 deg symmetrical and concave upward, and the energy distributions show that the alpha particles with energies below the Couloumb barrier are raore emitted than has been expected. The curves on a semilog plot of the relative level density calculated from the energy distributions of the alpha particles cannot fit a straight line. The total (n, alpha ) cross sections of cohalt end manganese are 84 mb plus or minus 15% and 96 mb plus or minus 15%, respectively. The results are compared with the predictions of the statistical theory of nuclear reactions. (auth)The angular and energy distributions of alpha particles resulting from Co 59 ( n , α)Mn 56 and Mn 55 ( n , α)V 52 reactions induced by 14.8-Mev neutrons were measured with Ilford C2 nuclear plates. As in the case of Al 27 ( n , α)Na 24 reaction, the angular distributions for the entire energy region are approximately 90° symmetrical and concave upward, and the energy distributions show that the alpha particles with energies below the Coulomb barrier are more emitted than has been expected. The curves on a semilog plot of the relative level density calculated from the energy distributions of the alpha particles cannot fit a straight line. The total ( n , α) cross sections of cobalt and manganese are 84 mb±15% and 96 mb±15% respectively. The results are compared with the predictions of the statistical theory of nuclear reactions.