| Popis: |
Measurements of the gamma rays excited by neutron inelastic scattering in B11, Na, Si, K, Sc, Zr, In, I, Ta, Au, Tl, and Pb206 have been carried out by use of the conventional ring scatterer geometry within a neutron energy range from 0.2 Mev to 3.5 Mev. The studies were used to obtain information on level structure, to determine cross sections for gamma-ray excitation, and to make a test of the predictions of inelastic scattering cross sections computed by a combination of the statistical and optical models. New levels and information on the decay schemes have been found in Zr, I, Au, and Pb206. Excitation functions in terms of absolute cross sections are presented for the prominent gamma rays in the spectra of all the elements studied except Sc and Tl. Studies of the gamma rays from Pb206 have given experimental verification of the level scheme for the low spin states calculated by True and Ford. Statistical model calculations are presented which give reasonably good agreement with the experiments on Pb206 provided the penetrabilities are calculated using parameters obtained from an analysis of elastic scattering data specifically for Pb206. The analysis shows that the imaginary part of the optical potential is abnormally low for Pb206 compared to that for neighboring nuclei at comparable energies. The agreement in magnitude and shape between the experimental and calculated excitation functions can be improved if the imaginary part of the potential is permitted to increase with neutron channel energy. |
