Excitation Of Giant Resonances In 20ne 90zr And 208pb Inelastic Scattering At 40 Mev U

Inelastic electron scattering experiments were performed with the Naval Postgraduate School 110 MeV Linac. The investigation included 238U, 140Ce, 89Y, 60Ni, 58Ni and 28Si, which combined with our previous studies of 208Pb, 197Au and 165Ho, form a survey of the giant resonances in many nuclei. The energy resolution of about 0.4% to 0.5%, was usually sufficient for studying these broad resonances; the excitation energy range covered was from 4 to 40 or 50 MeV, and showed giant resonances of energies from 6 to 33 MeV. Forward scattering angles were used resulting in only electric multipole resonances. The cerium experiment possibly revealed more than any other single nucleus studied. In addition to E2 Delta T =0) at 10 MeV and E1 at 15.3 MeV, the isovector E2 appears at 25 MeV. E3 resonances appear at 6.0 MeV, 22 MeV and 34638 MeV in general agreement with the model of Bohr and Mottelson. For Uranium, both quadrupole resonances were observed, but were low in strength unless a transition radius larger than the ground state radius was assumed. Systematics of the resonance at 53 cu.rt. (1/A) MeV showed a smooth and drastic decrease with strength as a function of decreasing A, a behavior not seen for the GQR at 63 cu.rt.(1/A) MeV. This suggests the former resonance is an oscillation of the excess neutron of a heavy nucleus.

Giant multipole resonances and bound states above 6 MeV in Ni 60 were studied with inelastic scattering of electrons at 102 MeV incident energy and scattering angles of 60, 75, 90, and 105 degrees. In the energy interval from 5 MeV to 40 MeV excitation energy, ten states and resonances were observed of which only those below 7 MeV and those at 16.5 and 18.5 had been previously reported. Reduced transition probabilities were calculated, and multipolarity assignments were made. The ten transitions were observed at excitation energies of 6.1 (E3,E2), 7.0 (E3,M2), 7.6 (E2,E3,M2), 8.4 (E2,E0), 9.9 (E1), 11.8 (E2,E0), 12.9 (E3,M2), 15.0 (E4), 16.5 (E2,E0), and 18.5 (E1) MeV. The E4 resonance at 15.0 MeV was previously unreported. The E2 resonance at 16.5 MeV reported in (alpha, alpha primed) work and the E1 resonance at 18.5 MeV from (Gamma, n) were confirmed. (Author).

Giant multipole resonances and bound states above 6 MeV in Ni 60 were studied with inelastic scattering of electrons at 102 MeV incident energy and scattering angles of 60, 75, 90, and 105 degrees. In the energy interval from 5 MeV to 40 MeV excitation energy, ten states and resonances were observed of which only those below 7 MeV and those at 16.5 and 18.5 had been previously reported. Reduced transition probabilities were calculated, and multipolarity assignments were made. The ten transitions were observed at excitation energies of 6.1 (E3,E2), 7.0 (E3,M2), 7.6 (E2,E3,M2), 8.4 (E2,E0), 9.9 (E1), 11.8 (E2,E0), 12.9 (E3,M2), 15.0 (E4), 16.5 (E2,E0), and 18.5 (E1) MeV. The E4 resonance at 15.0 MeV was previously unreported. The E2 resonance at 16.5 MeV reported in (alpha, alpha primed) work and the E1 resonance at 18.5 MeV from (Gamma, n) were confirmed. (Author).