Isomer Spectroscopy in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow></mrow><mrow><mn>90</mn></mrow><mrow><mn>216</mn></mrow></msubsup></mrow><mrow><msub><mrow><mi>Th</mi></mrow><mrow><mn>126</mn></mrow></msub></mrow></math></span> and the Magicity of <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow></mrow><mrow><mn>92</mn></mrow><mrow><mn>218</mn></mrow></msubsup></mrow><mrow><msub><mrow><mi>U</mi></mrow><mrow><mn>126</mn></mrow></msub></mrow></math></span>

K. Hauschild; M. Rejmund; H. Grawe; E. Caurier; F. Nowacki; F. Becker; Y. Le Coz; W. Korten; J. Döring; M. Górska; K. Schmidt; O. Dorvaux; K. Helariutta; P. Jones; R. Julin; S. Juutinen; H. Kettunen; M. Leino; M. Muikku; P. Nieminen; P. Rahkila; J. Uusitalo; F. Azaiez; M. Belleguic

doi:10.1103/PhysRevLett.87.072501

Isomer Spectroscopy in $_{90}^{216} {Th}_{126}$ and the Magicity of $_{92}^{218} U_{126}$

K. Hauschild, M. Rejmund, H. Grawe, E. Caurier, F. Nowacki, F. Becker, Y. Le Coz, W. Korten, J. Döring, M. Górska, K. Schmidt, O. Dorvaux, K. Helariutta, P. Jones, R. Julin, S. Juutinen, H. Kettunen, M. Leino, M. Muikku, P. Nieminen, P. Rahkila, J. Uusitalo, F. Azaiez, and M. Belleguic

Phys. Rev. Lett. 87, 072501 – Published 25 July 2001

Abstract

Excited states in $^{216} Th$ were investigated via prompt and delayed $γ$ decays and the recoil-decay tagging method. The decay schemes of the $I^{π} = (8^{+})$ , $t_{1 / 2} = 128 (8) μ s$ , the $I^{π} = (11^{-})$ , $t_{1 / 2} = 615 (55) ns$ , and the $I^{π} = (14^{+})$ , $t_{1 / 2} \geq 130 ns$ isomers were established. The configuration $π h_{9 / 2} f_{7 / 2}$ is assigned to the $I^{π} = (8^{+})$ isomer, which implies that the $h_{9 / 2}$ and $f_{7 / 2}$ states are nearly degenerate. This is ascribed to increased binding of the $f_{7 / 2}$ orbital by its coupling to a low-lying $I^{π} = (3^{-})$ state at $E_{x} = 1687 keV$ . The role of octupole and pairing correlations for a $Z = 92$ shell closure prediction is discussed on the basis of shell model calculations.

Received 9 May 2001

DOI:https://doi.org/10.1103/PhysRevLett.87.072501

Authors & Affiliations

K. Hauschild¹, M. Rejmund^2,*, H. Grawe², E. Caurier³, F. Nowacki³, F. Becker^1,†, Y. Le Coz¹, W. Korten¹, J. Döring², M. Górska², K. Schmidt², O. Dorvaux^4,‡, K. Helariutta^4,§, P. Jones⁴, R. Julin⁴, S. Juutinen⁴, H. Kettunen⁴, M. Leino⁴, M. Muikku^4,∥, P. Nieminen⁴, P. Rahkila⁴, J. Uusitalo⁴, F. Azaiez⁵, and M. Belleguic^5,¶

¹DAPNIA/SPhN CEA Saclay, F-91191 Gif-sur-Yvette, France
²Gesellschaft für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany
³IReS, F-67037 Strasbourg Cedex 2, France
⁴Accelerator Laboratory, University of Jyväskylä, P.O. Box 35, FIN-40351, Finland
⁵IPN, F-91406 Orsay Cedex, France

^*Present address: DAPNIA/SPhN CEA Saclay, F-91191 Gif-sur-Yvette, France.
^†Present address: GANIL, BP 5027, 14076 Caen Cedex 5, France.
^‡Present address: IReS, F-67037 Strasbourg Cedex 2, France.
^§Present address: Laboratory of Radiochemistry, 00014 University of Helsinki, Finland.
^∥Present address: Daresbury Laboratory, Warrington, WA4 4AD Cheshire, U.K.
^¶Present address: University of Surrey, Guildford GU2 7XH, U.K.