Systematic study of the fragmentation of low-lying dipole strength in odd-{ital A} rare earth nuclei investigated in nuclear resonance fluorescence experiments
- Institut fuer Strahlenphysik, Universitaet Stuttgart, Allmandring 3, D-70569 Stuttgart (Germany)
Nuclear resonance fluorescence experiments were performed on the rare earth nuclei {sup 155}Gd and {sup 159}Tb to study the fragmentation of the {ital M}1 {ital scissors} {ital mode} in {ital odd} deformed nuclei and to establish a kind of systematics. Using the bremsstrahlung photon beam of the Stuttgart Dynamitron (end point energy 4.1 MeV) and high resolution Ge-{gamma} spectrometers detailed information was obtained on excitation energies, decay widths, transition probabilities, and branching ratios. The results are compared to those observed recently for the neighboring odd nuclei {sup 161,163}Dy and {sup 157}Gd. Whereas in the odd Dy isotopes the dipole strength is rather concentrated, both Gd isotopes show a strong fragmentation of the strength into about 25 ({sup 155}Gd) and 90 transitions ({sup 157}Gd) in the energy range 2{endash}4 MeV. The nucleus {sup 159}Tb linking the odd Dy and Gd isotopes exhibits an intermediate strength fragmentation. In general the observed total strength in the odd nuclei is reduced by a factor of 2{endash}3 as compared to their neighboring even-even isotopes. The different fragmentation behavior of the dipole strengths in the odd Dy and Gd isotopes is unexplained up to now. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 390333
- Journal Information:
- Physical Review, C, Journal Name: Physical Review, C Journal Issue: 5 Vol. 54; ISSN PRVCAN; ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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