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Title: Nuclear shape and structure in neutron-rich {sup 110,111}Tc

Abstract

The high-spin nuclear structure of Tc isotopes is extended to more neutron-rich regions based on the measurements of prompt {gamma} rays from the spontaneous fission of {sup 252}Cf at the Gammasphere. The high-spin level scheme of N=67 neutron-rich {sup 110}Tc (Z=43) is established for the first time, and that of {sup 111}Tc is extended and expanded. The ground band of {sup 111}Tc reaches the band-crossing region, and the new observation of the weakly populated {alpha}=-1/2 member of the band provides important information on signature splitting. The systematics of band crossings in the isotopic and isotonic chains and a CSM calculation suggest that the band crossing of the ground band of {sup 111}Tc is due to alignment of a pair of h{sub 11/2} neutrons. The best fit to signature splitting, branching ratios, and excitations of the ground band of {sup 111}Tc by the rigid triaxial rotor plus particle model calculations result in a shape of {epsilon}{sub 2}=0.32 and {gamma}=-26 deg. for this nucleus. Its triaxiality is larger than that of {sup 107,109}Tc, which indicates increasing triaxiality in Tc isotopes with increasing neutron number. The identification of the weakly populated K+2 satellite band provides strong evidence for the large triaxiality of {supmore » 111}Tc. In {sup 110}Tc, the four lowest-lying levels observed are very similar to those in {sup 108}Tc. At an excitation of 478.9 keV above the lowest state observed, ten states of a {delta}I=1 band are observed. This band of {sup 110}Tc is very analogous to the {delta}I=1 bands in {sup 106,108}Tc, but it has greater and reversal signature splitting at higher spins.« less

Authors:
 [1];  [2]; ; ; ; ; ;  [1]; ;  [3];  [4];  [5];  [1];  [6];  [2];  [7];  [3];  [2];  [8]; more »;  [9];  [10];  [11];  [12] « less
  1. Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States)
  2. (United States)
  3. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  4. KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium)
  5. Physics Department, Tsinghua University, Beijing 100084 (China)
  6. (China)
  7. Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China)
  8. Mississippi State University, Drawer 5167, Mississippi State, Mississippi 39762 (United States)
  9. Flerov Laboratory for Nuclear Reactions, JINR, Dubna (Russian Federation)
  10. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
  11. Universidade Federal do Rio de Janeiro, CP 68528, RG (Brazil)
  12. Institut fuer Kernphysik, Universitaet zu Koeln, D-50937, Cologne (Germany)
Publication Date:
OSTI Identifier:
20863704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 74; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevC.74.024308; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BRANCHING RATIO; CALIFORNIUM 252; ENERGY LEVELS; EXCITATION; GAMMA RADIATION; KEV RANGE; NEUTRONS; NUCLEAR STRUCTURE; PARTICLE-CORE COUPLING MODEL; SPIN; SPONTANEOUS FISSION; TECHNETIUM 108; TECHNETIUM 109; TECHNETIUM 110; TECHNETIUM 111

Citation Formats

Luo, Y. X., Lawrence Berkeley National Laboratory, Berkeley, California 94720, Hamilton, J. H., Ramayya, A. V., Hwang, J. K., Gore, P. M., Jones, E. F., Fong, D., Rasmussen, J. O., Lee, I. Y., Stefanescu, I., Che, X. L., Zhu, S. J., Physics Department, Tsinghua University, Beijing 100084, Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831, Wu, S. C., Ginter, T. N., National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, Ma, W. C., Ter-Akopian, G. M., Daniel, A. V., Stoyer, M. A., Donangelo, R., and Gelberg, A. Nuclear shape and structure in neutron-rich {sup 110,111}Tc. United States: N. p., 2006. Web. doi:10.1103/PHYSREVC.74.024308.
Luo, Y. X., Lawrence Berkeley National Laboratory, Berkeley, California 94720, Hamilton, J. H., Ramayya, A. V., Hwang, J. K., Gore, P. M., Jones, E. F., Fong, D., Rasmussen, J. O., Lee, I. Y., Stefanescu, I., Che, X. L., Zhu, S. J., Physics Department, Tsinghua University, Beijing 100084, Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831, Wu, S. C., Ginter, T. N., National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, Ma, W. C., Ter-Akopian, G. M., Daniel, A. V., Stoyer, M. A., Donangelo, R., & Gelberg, A. Nuclear shape and structure in neutron-rich {sup 110,111}Tc. United States. doi:10.1103/PHYSREVC.74.024308.
Luo, Y. X., Lawrence Berkeley National Laboratory, Berkeley, California 94720, Hamilton, J. H., Ramayya, A. V., Hwang, J. K., Gore, P. M., Jones, E. F., Fong, D., Rasmussen, J. O., Lee, I. Y., Stefanescu, I., Che, X. L., Zhu, S. J., Physics Department, Tsinghua University, Beijing 100084, Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831, Wu, S. C., Ginter, T. N., National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, Ma, W. C., Ter-Akopian, G. M., Daniel, A. V., Stoyer, M. A., Donangelo, R., and Gelberg, A. 2006. "Nuclear shape and structure in neutron-rich {sup 110,111}Tc". United States. doi:10.1103/PHYSREVC.74.024308.
@article{osti_20863704,
title = {Nuclear shape and structure in neutron-rich {sup 110,111}Tc},
author = {Luo, Y. X. and Lawrence Berkeley National Laboratory, Berkeley, California 94720 and Hamilton, J. H. and Ramayya, A. V. and Hwang, J. K. and Gore, P. M. and Jones, E. F. and Fong, D. and Rasmussen, J. O. and Lee, I. Y. and Stefanescu, I. and Che, X. L. and Zhu, S. J. and Physics Department, Tsinghua University, Beijing 100084 and Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831 and Wu, S. C. and Ginter, T. N. and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 and Ma, W. C. and Ter-Akopian, G. M. and Daniel, A. V. and Stoyer, M. A. and Donangelo, R. and Gelberg, A.},
abstractNote = {The high-spin nuclear structure of Tc isotopes is extended to more neutron-rich regions based on the measurements of prompt {gamma} rays from the spontaneous fission of {sup 252}Cf at the Gammasphere. The high-spin level scheme of N=67 neutron-rich {sup 110}Tc (Z=43) is established for the first time, and that of {sup 111}Tc is extended and expanded. The ground band of {sup 111}Tc reaches the band-crossing region, and the new observation of the weakly populated {alpha}=-1/2 member of the band provides important information on signature splitting. The systematics of band crossings in the isotopic and isotonic chains and a CSM calculation suggest that the band crossing of the ground band of {sup 111}Tc is due to alignment of a pair of h{sub 11/2} neutrons. The best fit to signature splitting, branching ratios, and excitations of the ground band of {sup 111}Tc by the rigid triaxial rotor plus particle model calculations result in a shape of {epsilon}{sub 2}=0.32 and {gamma}=-26 deg. for this nucleus. Its triaxiality is larger than that of {sup 107,109}Tc, which indicates increasing triaxiality in Tc isotopes with increasing neutron number. The identification of the weakly populated K+2 satellite band provides strong evidence for the large triaxiality of {sup 111}Tc. In {sup 110}Tc, the four lowest-lying levels observed are very similar to those in {sup 108}Tc. At an excitation of 478.9 keV above the lowest state observed, ten states of a {delta}I=1 band are observed. This band of {sup 110}Tc is very analogous to the {delta}I=1 bands in {sup 106,108}Tc, but it has greater and reversal signature splitting at higher spins.},
doi = {10.1103/PHYSREVC.74.024308},
journal = {Physical Review. C, Nuclear Physics},
number = 2,
volume = 74,
place = {United States},
year = 2006,
month = 8
}
  • The structure of Tc nuclei is extended to the moreneutron-rich regions based on measurements of prompt gamma rays from thespontaneous fission of 252Cf at Gammasphere. The level scheme of N=67neutron-rich (Z=43) 110Tc is established for the first time and that of111Tc is expanded. The ground-state band of 111Tc reaches theband-crossing region and the new observation of the weakly populatedalpha = -1/2 member of the band provides important information ofsignature splitting. The systematics of band crossings in the isotopicand isotonic chains and a CSM calculation suggest that the band crossingof the gs band of 111Tc is due to alignment of amore » pair of h11/2 neutrons.The best fit to signature splitting, branching ratios, and excitations ofthe ground-state band of 111Tc by RTRP model calculations result in ashape of epsilon2 = 0.32 and gamma = -26 deg. for this nucleus. Itstriaxiality is larger than that of 107Tc, to indicate increasingtriaxiality with increasing neutron number. The identification of theweakly-populated "K+2 satellite" band provides strong evidence for thelarge triaxiality of 111Tc. In 110Tc the four lowest-lying levelsobserved are very similar to those in 108Tc. At an excitation of 478.9keV above the lowest state observed, ten states of a delta I = 1 band areobserved. This band is very analogous to the delta I = 1 bands in106,108Tc, but it has greater signature splitting at higherspins.« less
  • The neutron-deficient and neutron-rich zirconium nuclei are studied using statistical theory. The deformation dependence of occupation numbers of the neutron orbitals in these nuclei near the Fermi level is investigated. The preference of the neutrons to occupy or vacate a particular orbital is found to contribute a particular shape to the nucleus. {copyright} {ital 1997} {ital The American Physical Society}
  • The shell structure underlying shape changes in neutron-rich nuclei near N=28 has been investigated by a novel application of the transient-field technique to measure the first-excited-state g factors in {sup 38}S and {sup 40}S produced as fast radioactive beams. There is a fine balance between proton and neutron contributions to the magnetic moments in both nuclei. The g factor of deformed {sup 40}S does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.
  • B(E2;2{sub 1}{sup +}{yields}0{sub 1}{sup +}) values have been measured for the unstable nuclei {sup 88}Kr (N = 52) and {sup 92}Kr (N = 56) using projectile Coulomb excitation at ISOLDE, CERN. With this experiment the local maximum in E(2{sub 1}{sup +}) in {sup 92}Kr and the role of the N = 56 subshell closure can be studied.
  • The effect of projectile shape on cross sections and momentum distributions of fragments from heavy ion reactions is studied. We propose a new approach that implements the underlying symmetries of each isotope with a few parameters directly in the density. Various densities and their nuclear structure are analyzed in the reactions of {sup 12}C and {sup 11}Li, {sup 11}Be, and {sup 11}C on a carbon target. {copyright} {ital 1996 The American Physical Society.}