2018 Impact factor 2.481
Hadrons and Nuclei
Eur. Phys. J. A 16, 457-467 (2003)
DOI: 10.1140/epja/i2002-10130-9

Investigations into the alpha-decay of $\chem{^{195}At}$

H. Kettunen1, T. Enqvist1, M. Leino1, K. Eskola2, P.T. Greenlees1, K. Helariutta1, P. Jones1, R. Julin1, S. Juutinen1, H. Kankaanpää1, H. Koivisto1, P. Kuusiniemi1, M. Muikku1, P. Nieminen1, P. Rahkila1 and J. Uusitalo1

1  Department of Physics, University of Jyväskylä, P.O. Box 35, FIN-40014 Jyväskylä, Finland
2  Department of Physical Sciences, University of Helsinki, FIN-00014 Helsinki, Finland

heikki.kettunen@phys.jyu.fi

(Received: 16 September 2002 / Revised version: 4 December 2002 / Published online: 25 March 2003)

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 $E_{\alpha}=6953(3)$ keV and a half-life T1/2=328(20) ms. Another state with an alpha-decay energy $E_{\alpha}=7075(4)$ 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 - $190 \leq A \leq 219$ .
23.20.Lv - Gamma transitions and level energies.
21.10.Dr - Binding energies and masses.

© Società Italiana di Fisica, Springer-Verlag 2003