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Investigations into the alpha-decay of 195At

  • H. Kettunen
  • T. Enqvist
  • M. Leino
  • K. Eskola
  • P.T. Greenlees
  • K. Helariutta
  • P. Jones
  • R. Julin
  • S. Juutinen
  • H. Kankaanpää
  • H. Koivisto
  • P. Kuusiniemi
  • M. Muikku
  • P. Nieminen
  • P. Rahkila
  • J. Uusitalo

Abstract:

The low-energy nuclear structure and decay properties of the neutron-deficient isotopes 195At and 191Bi have been studied. 195At was produced in the reaction 142Nd(56Fe,p2n)195At and 191Bi as the daughter activity of 195At. The activities were implanted in a position-sensitive silicon detector after being separated from the primary beam by a gas-filled recoil separator. The 1/2+ intruder state was determined to be the ground state in 195At with an alpha-decay energy of Eα = 6953(3) keV and a half-life T1/2 = 328(20) ms. Another state with an alpha-decay energy Eα = 7075(4) keV and a half-life T1/2 = 147(5) ms was found to decay to a 148.7(5) keV excited state in 191Bi for which a spin and parity of 7/2- were deduced. Consequently, the same 7/2- character was assigned to the initial state at 32(7) keV in 195At on the basis of unhindered alpha-decay. The 9/2- state, being the ground state in heavier odd-mass astatine isotopes, was not observed.

PACS. 23.60.+e Alpha decay – 27.80.+w 190 ⩽ A ⩽ 219 – 23.20.Lv Gamma transitions and level energies – 21.10.Dr Binding energies and masses 

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Copyright information

© Società Italiana di Fisica and Springer-Verlag 2003

Authors and Affiliations

  • H. Kettunen
    • 1
  • T. Enqvist
    • 1
  • M. Leino
    • 1
  • K. Eskola
    • 2
  • P.T. Greenlees
    • 1
  • K. Helariutta
    • 1
  • P. Jones
    • 1
  • R. Julin
    • 1
  • S. Juutinen
    • 1
  • H. Kankaanpää
    • 1
  • H. Koivisto
    • 1
  • P. Kuusiniemi
    • 1
  • M. Muikku
    • 1
  • P. Nieminen
    • 1
  • P. Rahkila
    • 1
  • J. Uusitalo
    • 1
  1. 1.Department of Physics, University of Jyväskylä, P.O. Box 35, FIN-40014 Jyväskylä, FinlandFI
  2. 2.Department of Physical Sciences, University of Helsinki, FIN-00014 Helsinki, FinlandFI

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