α decay of a new isotope <SUP>209</SUP>Th

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• Ikuta, T.
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• Hamada, S.
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• Nagame, Y.
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• Nishinaka, I.
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• Tsukada, K.
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• Oura, Y.
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• Ohtsuki, T.

Abstract

The new neutron deficient isotope ²⁰⁹Th has been produced in the reaction of ³²S on ¹⁸²W at beam energy of 171 MeV. Evaporation residues were separated in flight from beam by a JAERI recoil mass separator, and implanted in a position sensitive strip detector. The genetic correlation of α-decay events, their energies and half-lives has been used to identify isotopes. An α-decay energy and a half-life of ²⁰⁹Th have been determined to be 8.080(50) MeV and 3.8^+6.9_-1.5 ms, respectively.