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Title: Multipole moments of /sup 232/Th, /sup 234/ /sup 236/ /sup 238/U using proton inelastic scattering

Thesis/Dissertation ·
OSTI ID:5986922

The multipole moments of /sup 232/Th, /sup 234/ /sup 236/ /sup 238/U have been determined using proton scattering at 35.3 MeV. The angular distributions of scattered protons for the elastic J/sup ..pi../ = 0/sup +/) and ground state rotational band states (J/sup ..pi../ = 2/sup +/, 4/sup +/, 6/sup +/, 8/sup +/) were extracted for laboratory angles from 20 to 144.5 degrees. The targets were UF/sub 4/ and ThF/sub 4/ and isotopically separated for /sup 234/ /sup 236/U. The scattered protons were detected using a position sensitive detector in the focal plane of an Enge split-role spectrograph. The typical energy resolution of keV is made possible by using dispersion matching for the entire range of scattering angles. The data were analyzed using coupled channels calculations for scattering from a rigid rotor via a deformed optical model potential. Automatic searches were made on a number of model parameters, including the deformation parameters ..beta../sub 2/, ..beta../sub 4/, ..beta../sub 6/ for both spherical and deformed spinorbit potentials. The quadrupole hexadecapole and hexakontattetarapole moments were calculated from the parameter values and compared with the results of Coulomb excitation, electron scattering, inelastic alpha scattering and with predictions of microscopic calculations. Improved fits to the data were obtained by including the higher order deformations. Comparisons were made for a full deformed spin-orbit potential and a spherical spin-orbit potential, with the deformed spin-orbit yielding improved fits. The resultant quadrupole moments increase in magnitude with increasing nuclear mass in agreement with Coulomb excitation results but systematically 3% to 5% lower. The present results are 3 to 6% higher than those predicted by microscopic calculations.

Research Organization:
Michigan State Univ., East Lansing (USA)
OSTI ID:
5986922
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English