I. TENSOR-FORCE EFFECTS IN THE NUCLEAR SHELL THEORY. II. NUCLEAR SPECTROSCOPIC STUDIES OF ISOMERIC STATES IN ODD-ODD YTTRIUM NUCLEI (thesis)

Technical Report · Wed Jun 12 04:00:00 EDT 1963

OSTI ID:4663735

Kim, Y E

The low-lying energy levels of odd-odd nuclei near the doubly closed shell (Y/sup 90/, Bi/sup 208/, Bi/sup 210/, and Tl/sup 208/) are c alculated with finite-range central and tensor forces to the first order by means of the j-j coupled odd-group model. The two-body matrix elements for the central and tensor forces are expressed in the j-j representation, from which a generalization to off-diagonal matrix elements is obtained in the limit of zero range. A nucleon- nucleon Gaussian potential without a hard core based on the free two-nucleon potentials of Blatt-Jackson and Brueckner-Gammel-Thaler is used for the residual interaction. Eigenvalues and eigenvectors are presented and compared with experimental spectra. The tensor-force effects are examined in detail as a function of the force range for the nuclei Y/sup 90/ and Bi/sup 210/. A tensor force with reasonable range and strength accounts for the 1- state of the h/sub 9/ 2 g/sub 9/2/ multiplet being the ground state of Bi/sup 210/ instead of the O/sup -/ predicted by central forces. The low-lying energy levels of Po/sup 210/ are also calculated with the same residual force used for Bi/sup 210/ in order to obtain the RaE beta-decay matrix-element ratio i(r)/( sigma xr). It is shown that the ground-state wave functions for Bi/sup 210/ and Po/sup 210/ are consistent with the experimentally determined RaE betadecay matrix-element ratio and the measured magnetic dipole moment of Bi/sup 210/. The ground-state wave function for Y/sup 90/ is also consistent with the measured magnetic dipole moment of Y/sup 90/. A high-spin (J = 11) isomeric state in Po/sup 210/ is predicted with an estimated gamma partial lifetime of the order of microseconds. A 48 plus or minus 1 min isomeric level in Y/sup 90/ was produced by irradiations of rubidium (natural and enriched in Rb/sup 85/) with alpha particles and of strontium (flatural and enriched in Sr/sup 86/ ) with deuterons. Two transitions with energies 10.15 plus or minus 0.1 and 208.0 plus or minus 0.3 kev were observed in the decay of Y/sup 86m/. From the L sub-shell ratios the multipolarity of the 10-kev transition was determined to be E3. The K- conversion coeificient of the 208-kev transition is epsilon /sub K/ = 0.04 plus or minus 0.01. A possible decay scheme of Y/sup 86m/ is suggested. The energy of the isomeric transition in Y/sup 90m/ was measured to be 202.4 plus or minus 0.3 kev by use of a permanentmagnet 180 deg spectrograph. 95 references. (auth)

• Research Organization: California. Univ., Berkeley. Lawrence Radiation Lab.
• DOE Contract Number: W-7405-ENG-48
• NSA Number: NSA-17-034887
• OSTI ID: 4663735
• Report Number(s): UCRL-10865
• Country of Publication: United States
• Language: English

Related Subjects

BETA DECAY
BIBLIOGRAPHY
BINDING ENERGY
BISMUTH 208
BISMUTH 210
BRUECKNER METHOD
CONFIGURATION
DEUTERONS
EIGENVALUES
ENERGY LEVELS
ENRICHMENT
EXCHANGE MODEL
GAMMA RADIATION
GAUSS POTENTIAL
INTERACTIONS
INTERNAL CONVERSION
IRRADIATION
ISOMERS
J-J COUPLING
LIFETIME
MAGNETIC MOMENTS
MAGNETS
MANY BODY PROBLEM
MATHEMATICS
MATRICES
NUCLEAR MODELS
NUCLEI
NUCLEONS
NUMERICALS
ORBITS
PHYSICS
POLONIUM 210
QUANTUM MECHANICS
REACTION KINETICS
RUBIDIUM
RUBIDIUM 85
SHELL MODELS
SPECTRA
SPECTROSCOPY
SPIN
STRONTIUM 86
TENSOR FORCES
THALLIUM 208
TRANSIENTS
VECTORS
YTTRIUM 86
YTTRIUM 90
ZERO-RANGE APPROXIMATION