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Title: Population and decay of high-spin states in /sup 157-161/Yb: evolution of nuclear shapes as a function spin and neutron number

Abstract

The population and decay of the entry states in /sup 157-161/Yb and /sup 155-158/Er from the reactions of 136- and 149-MeV /sup 20/Ne with /sup 144/Nd and /sup 146/Nd have been investigated with the Spin Spectrometer gated with a Ge detector. Statistical-model calculations reproduce the main features of the entry state populations. The entry lines, as a function of multiplicity, M/sub ..gamma../ show changes in slope at high M/sub ..gamma../ which are due to changes in the decay mode as a result of changes in nuclear structure. Energy spectra of the continuum ..gamma..-rays and angular distributions as a function of M/sub ..gamma../ show the onset of a dipole component localized at 650 +- 100 keV accompanied by an equally intense quadrupole component at twice the energy that continues to evolve to higher energies with increasing multiplicity. For /sup 157/ /sup 158/ /sup 159/ /sup 160/ /sup 161/Yb the dipole component appears at M/sub ..gamma../ = 21,22,23,25, and 27 (at spin I approx. = 38,40,42,45, and 50), respectively. At precisely these multiplicities the entry lines show a decrease in slope. In /sup 158/Yb the dipole component disappears at M/sub ..gamma../ = 28 and the entry line resumes its original slope. Themore » results are consistent with the following picture. At low spins for /sup 157/ /sup 158/Yb the nuclear shapes evolve from prolate to slightly oblate particle-aligned structures. At I approx. = 38,40,42,45, and 50 the /sup 157/ /sup 158/ /sup 159/ /sup 160/ /sup 161/Yb nuclei, respectively, develop high-K rotational bands which may be built on oblate structures with large deformation (epsilon approx. = 0.3). At I = 49 a transition to triaxial shape appears to occur in /sup 158/Yb.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Washington Univ., St. Louis, MO (USA). Dept. of Chemistry
OSTI Identifier:
5101118
Report Number(s):
CONF-820738-1
ON: DE82018159
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Technical Report
Resource Relation:
Conference: INS symposium on dynamics of nuclear collective motion, Mount Fuji, Japan, 6 Jul 1982
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; YTTERBIUM 157; HIGH SPIN STATES; MULTIPOLE TRANSITIONS; YTTERBIUM 158; YTTERBIUM 159; YTTERBIUM 160; YTTERBIUM 161; ANGULAR DISTRIBUTION; ENERGY-LEVEL TRANSITIONS; EXPERIMENTAL DATA; FUSION REACTIONS; GAMMA RADIATION; GAMMA SPECTRA; MEV RANGE 100-1000; MOMENT OF INERTIA; MULTIPLICITY; NEODYMIUM 144 TARGET; NEODYMIUM 146 TARGET; NEON 20 REACTIONS; ROTATIONAL STATES; SPIN; ALPHA DECAY RADIOISOTOPES; ANGULAR MOMENTUM; CHARGED-PARTICLE REACTIONS; DATA; DISTRIBUTION; ELECTROMAGNETIC RADIATION; ENERGY LEVELS; ENERGY RANGE; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; EXCITED STATES; HEAVY ION REACTIONS; INFORMATION; INTERMEDIATE MASS NUCLEI; IONIZING RADIATIONS; ISOTOPES; MEV RANGE; MINUTES LIVING RADIOISOTOPES; NUCLEAR REACTIONS; NUCLEI; NUMERICAL DATA; PARTICLE PROPERTIES; RADIATIONS; RADIOISOTOPES; RARE EARTH ISOTOPES; RARE EARTH NUCLEI; SECONDS LIVING RADIOISOTOPES; SPECTRA; TARGETS; YTTERBIUM ISOTOPES; 651823* - Nuclear Properties & Reactions, A=150-189, Experimental- Energy Levels & Transitions- (-1987)

Citation Formats

Jaeaeskelaeinen, M, Sarantites, D G, Dilmanian, F A, Woodward, R, Puchta, H, Beene, J R, Halbert, M L, Hattula, J, Hensley, D C, and Barker, J H. Population and decay of high-spin states in /sup 157-161/Yb: evolution of nuclear shapes as a function spin and neutron number. United States: N. p., 1982. Web. doi:10.2172/5101118.
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Jaeaeskelaeinen, M, Sarantites, D G, Dilmanian, F A, Woodward, R, Puchta, H, Beene, J R, Halbert, M L, Hattula, J, Hensley, D C, & Barker, J H. Population and decay of high-spin states in /sup 157-161/Yb: evolution of nuclear shapes as a function spin and neutron number. United States. https://doi.org/10.2172/5101118
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Jaeaeskelaeinen, M, Sarantites, D G, Dilmanian, F A, Woodward, R, Puchta, H, Beene, J R, Halbert, M L, Hattula, J, Hensley, D C, and Barker, J H. 1982. "Population and decay of high-spin states in /sup 157-161/Yb: evolution of nuclear shapes as a function spin and neutron number". United States. https://doi.org/10.2172/5101118. https://www.osti.gov/servlets/purl/5101118.
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@article{osti_5101118,
title = {Population and decay of high-spin states in /sup 157-161/Yb: evolution of nuclear shapes as a function spin and neutron number},
author = {Jaeaeskelaeinen, M and Sarantites, D G and Dilmanian, F A and Woodward, R and Puchta, H and Beene, J R and Halbert, M L and Hattula, J and Hensley, D C and Barker, J H},
abstractNote = {The population and decay of the entry states in /sup 157-161/Yb and /sup 155-158/Er from the reactions of 136- and 149-MeV /sup 20/Ne with /sup 144/Nd and /sup 146/Nd have been investigated with the Spin Spectrometer gated with a Ge detector. Statistical-model calculations reproduce the main features of the entry state populations. The entry lines, as a function of multiplicity, M/sub ..gamma../ show changes in slope at high M/sub ..gamma../ which are due to changes in the decay mode as a result of changes in nuclear structure. Energy spectra of the continuum ..gamma..-rays and angular distributions as a function of M/sub ..gamma../ show the onset of a dipole component localized at 650 +- 100 keV accompanied by an equally intense quadrupole component at twice the energy that continues to evolve to higher energies with increasing multiplicity. For /sup 157/ /sup 158/ /sup 159/ /sup 160/ /sup 161/Yb the dipole component appears at M/sub ..gamma../ = 21,22,23,25, and 27 (at spin I approx. = 38,40,42,45, and 50), respectively. At precisely these multiplicities the entry lines show a decrease in slope. In /sup 158/Yb the dipole component disappears at M/sub ..gamma../ = 28 and the entry line resumes its original slope. The results are consistent with the following picture. At low spins for /sup 157/ /sup 158/Yb the nuclear shapes evolve from prolate to slightly oblate particle-aligned structures. At I approx. = 38,40,42,45, and 50 the /sup 157/ /sup 158/ /sup 159/ /sup 160/ /sup 161/Yb nuclei, respectively, develop high-K rotational bands which may be built on oblate structures with large deformation (epsilon approx. = 0.3). At I = 49 a transition to triaxial shape appears to occur in /sup 158/Yb.},
doi = {10.2172/5101118},
url = {https://www.osti.gov/biblio/5101118}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1982},
month = {Fri Jan 01 00:00:00 EST 1982}
}
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Technical Report:
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https://doi.org/10.2172/5101118
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