Rigidity of the DoublyMagic ^{100}Sn Core
(1998) In Cosmic and Subatomic Physics Dissertation Abstract
 The doubly magic nucleus <sup>100</sup>Sn represents a crucial test for the nuclear shell model, which is a widely used model for a quantitative description of nuclei. Excited states in <sup>100</sup>Sn are experimentally not accessible with present day techniques, but it is possible to gain insight into its structure by studying the properties of excited states of neighboring nuclei. These nuclei are by themselves very interesting since they enable the determination of singleparticle energies and twobody matrix elements, which are the basic parameters of the shell model. Excited states of nuclei in the vicinity of <sup>100</sup>Sn have been studied in a series of experiments using three different... (More)
 The doubly magic nucleus <sup>100</sup>Sn represents a crucial test for the nuclear shell model, which is a widely used model for a quantitative description of nuclei. Excited states in <sup>100</sup>Sn are experimentally not accessible with present day techniques, but it is possible to gain insight into its structure by studying the properties of excited states of neighboring nuclei. These nuclei are by themselves very interesting since they enable the determination of singleparticle energies and twobody matrix elements, which are the basic parameters of the shell model. Excited states of nuclei in the vicinity of <sup>100</sup>Sn have been studied in a series of experiments using three different experimental setups. The first experiment utilized the NORDBALL detector array where for the first time excited states in the T<sub>z</sub>=3/2 nuclei <sup>99</sup>Cd and <sup>101</sup>In were identified. In addition, the level schemes of several nuclei with previously known excited states were significantly extended. The nuclei <sup>103</sup>In, <sup>105</sup>In, <sup>107</sup>In and <sup>109</sup>In are described in this thesis. The following experiments used a recoil catcher setup in combination with two EUROBALL cluster detectors, where for the first time excited states in the T<sub>z</sub>=1 nuclei <sup>98</sup>Cd and <sup>102</sup>Sn were identified. These two nuclei are now the nearest neighbors of <sup>100</sup>Sn with known excited states. The last three experiments used the Fragment Mass Analyzer at Argonne National Laboratory to study <sup>102</sup>Sn in more detail. In all experiments a beam of <sup>58</sup>Ni ions was used to bombard targets of <sup>46</sup>Ti and <sup>50</sup>Cr. The experimental level schemes of <sup>98</sup>Cd, <sup>99</sup>Cd, <sup>102</sup>Sn and <sup>103</sup>In are well reproduced by the shell model calculations. Isomeric states were found in <sup>98</sup>Cd, <sup>99</sup>Cd and <sup>102</sup>Sn and their halflives were measured. The isomeric states in all three nuclei decay via low energy E2 transitions. The deduced E2 transition rates lead to controversial results for the proton and neutron effective charges, which are also basic shell model parameters. In <sup>102</sup>Sn the measured B(E2;6<sup>+</sup>4<sup>+</sup>) value leads to a neutron effective charge of 2.0<sup>+0.5</sup><sub>0.3</sub>e, which is a fairly large value. The analysis of the isomeric 17/2<sup>+</sup> state in <sup>99</sup>Cd suggests a proton effective charge of 1.4(1) e, whereas the measured B(E2;8<sup>+</sup>6<sup>+</sup>) value in <sup>98</sup>Cd requires a proton effective charge of only 0.93<sup>+0.14</sup><sub>0.10</sub>e. The small proton effective charge in <sup>98</sup>Cd is very surprising, since it is even smaller than the bare proton charge. In all other nuclei studied so far, the effective charges are larger than the bare nucleon charges, and usually the neutron effective charge is lower than the proton effective charge. The large neutron effective charge points to a softness of the <sup>100</sup>Sn core with respect to quadrupole shape changes, whereas the two proton holes weakly polarize the core in <sup>99</sup>Cd and not at all in <sup>98</sup>Cd. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/38753
 author
 Lipoglavsek, Matej ^{LU}
 supervisor
 opponent

 Dr Fogelberg, Birger, Uppsala University
 organization
 publishing date
 1998
 type
 Thesis
 publication status
 published
 subject
 keywords
 inbeam gammaray spectrscopy, nuclear structure, fusionevaporation reactions, nuclear shell model, quadrupole polarization charge, doublymagic nucleus, Nuclear physics, Kärnfysik, Fysicumarkivet A:1998:Lipoglavšek
 in
 Cosmic and Subatomic Physics Dissertation
 pages
 131 pages
 publisher
 Division of Cosmic and Subatomic Physics, Department of Physics, Lund University
 defense location
 Hall B, Department of Physics
 defense date
 19980529 13:15:00
 external identifiers

 other:ISRN: LUNFD6/NFFK98/1014SE+131P
 ISSN
 11014202
 ISBN
 9162829475
 language
 English
 LU publication?
 yes
 id
 1bb11e4bb0984b2aa55bbbfaa68c19d1 (old id 38753)
 date added to LUP
 20160401 15:52:01
 date last changed
 20190521 12:34:51
@phdthesis{1bb11e4bb0984b2aa55bbbfaa68c19d1, abstract = {The doubly magic nucleus <sup>100</sup>Sn represents a crucial test for the nuclear shell model, which is a widely used model for a quantitative description of nuclei. Excited states in <sup>100</sup>Sn are experimentally not accessible with present day techniques, but it is possible to gain insight into its structure by studying the properties of excited states of neighboring nuclei. These nuclei are by themselves very interesting since they enable the determination of singleparticle energies and twobody matrix elements, which are the basic parameters of the shell model. Excited states of nuclei in the vicinity of <sup>100</sup>Sn have been studied in a series of experiments using three different experimental setups. The first experiment utilized the NORDBALL detector array where for the first time excited states in the T<sub>z</sub>=3/2 nuclei <sup>99</sup>Cd and <sup>101</sup>In were identified. In addition, the level schemes of several nuclei with previously known excited states were significantly extended. The nuclei <sup>103</sup>In, <sup>105</sup>In, <sup>107</sup>In and <sup>109</sup>In are described in this thesis. The following experiments used a recoil catcher setup in combination with two EUROBALL cluster detectors, where for the first time excited states in the T<sub>z</sub>=1 nuclei <sup>98</sup>Cd and <sup>102</sup>Sn were identified. These two nuclei are now the nearest neighbors of <sup>100</sup>Sn with known excited states. The last three experiments used the Fragment Mass Analyzer at Argonne National Laboratory to study <sup>102</sup>Sn in more detail. In all experiments a beam of <sup>58</sup>Ni ions was used to bombard targets of <sup>46</sup>Ti and <sup>50</sup>Cr. The experimental level schemes of <sup>98</sup>Cd, <sup>99</sup>Cd, <sup>102</sup>Sn and <sup>103</sup>In are well reproduced by the shell model calculations. Isomeric states were found in <sup>98</sup>Cd, <sup>99</sup>Cd and <sup>102</sup>Sn and their halflives were measured. The isomeric states in all three nuclei decay via low energy E2 transitions. The deduced E2 transition rates lead to controversial results for the proton and neutron effective charges, which are also basic shell model parameters. In <sup>102</sup>Sn the measured B(E2;6<sup>+</sup>4<sup>+</sup>) value leads to a neutron effective charge of 2.0<sup>+0.5</sup><sub>0.3</sub>e, which is a fairly large value. The analysis of the isomeric 17/2<sup>+</sup> state in <sup>99</sup>Cd suggests a proton effective charge of 1.4(1) e, whereas the measured B(E2;8<sup>+</sup>6<sup>+</sup>) value in <sup>98</sup>Cd requires a proton effective charge of only 0.93<sup>+0.14</sup><sub>0.10</sub>e. The small proton effective charge in <sup>98</sup>Cd is very surprising, since it is even smaller than the bare proton charge. In all other nuclei studied so far, the effective charges are larger than the bare nucleon charges, and usually the neutron effective charge is lower than the proton effective charge. The large neutron effective charge points to a softness of the <sup>100</sup>Sn core with respect to quadrupole shape changes, whereas the two proton holes weakly polarize the core in <sup>99</sup>Cd and not at all in <sup>98</sup>Cd.}, author = {Lipoglavsek, Matej}, isbn = {9162829475}, issn = {11014202}, language = {eng}, publisher = {Division of Cosmic and Subatomic Physics, Department of Physics, Lund University}, school = {Lund University}, series = {Cosmic and Subatomic Physics Dissertation}, title = {Rigidity of the DoublyMagic <sup>100</sup>Sn Core}, year = {1998}, }