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Hyperfine interactions and nuclear structure

Citation

Levanoni, Menachem (1970) Hyperfine interactions and nuclear structure. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/T2BF-B527. https://resolver.caltech.edu/CaltechTHESIS:08072015-133942509

Abstract

An automatic experimental apparatus for perturbed angular correlation measurements, capable of incorporating Ge(Li) detectors as well as scintillation counters, has been constructed.

The gamma-gamma perturbed angular correlation technique has been used to measure magnetic dipole moments of several nuclear excited states in the osmium transition region. In addition, the hyperfine magnetic fields, experienced by nuclei of 'impurity' atoms embedded in ferromagnetic host lattices, have been determined for several '4d' and '5d' impurity atoms.

The following magnetic dipole moments were obtained in the osmium transition region μ2+(190Os) = 0.54 ± 0.06 nm μ4+(190Os) = 0.88 ± 0.48 nm μ2+(192Os) = 0.56 ± 0.08 nm μ2+(192Pt) = 0.56 ± 0.06 nm μ2+’(192Pt) = 0.62 ± 0.14 nm.

These results are discussed in terms of three collective nuclear models; the cranking model, the rotation-vibration model and the pairing-plus-quadrupole model. The measurements are found to be in satisfactory agreement with collective descriptions of low lying nuclear states in this region.

The following hyperfine magnetic fields of 'impurities' in ferromagnetic hosts were determined; Hint(Cd Ni) = - (64.0 ± 0.8)kG Hint(Hg Fe) = - (440 ± 105)kG Hint(Hg Co) = - (370 ± 78)kG Hint(Hg Ni) = - (86 ± 22)kG Hint(Tl Fe) = - (185 ± 70)kG Hint(Tl Co) = - (90 ± 35)kG Hint(Ra Fe) = - (105 ± 20)kG Hint(Ra Co) = - (80 ± 16)kG Hint(Ra Ni) = - (30 ± 10)kG, where in Hint(AB); A is the impurity atom embedded in the host lattice B. No quantitative theory is available for comparison. However, these results are found to obey the general systematics displayed by these fields. Several mechanisms which may be responsible for the appearance of these fields are mentioned.

Finally, a theoretical expression for time-differential perturbed angular correlation measurement, which duplicates experimental conditions is developed and its importance in data analysis is discussed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Physics
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Boehm, Felix H.
Thesis Committee:
  • Unknown, Unknown
Defense Date:13 March 1970
Funders:
Funding AgencyGrant Number
Atomic Energy CommissionUNSPECIFIED
Record Number:CaltechTHESIS:08072015-133942509
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:08072015-133942509
DOI:10.7907/T2BF-B527
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9087
Collection:CaltechTHESIS
Deposited By: Bianca Rios
Deposited On:10 Aug 2015 16:10
Last Modified:20 Dec 2019 20:00

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