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Phys. Rev. Lett. 80, 2085 - 2088 (1998)

β+ Decay Partial Half-Life of 54Mn and Cosmic Ray Chronometry

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A. H. Wuosmaa, I. Ahmad, S. M. Fischer, J. P. Greene, G. Hackman, V. Nanal, G. Savard, J. P. Schiffer, and P. Wilt
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439

Sam M. Austin and B. A. Brown
National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824

S. J. Freedman
Lawrence Berkeley National Laboratory and Department of Physics, University of California, Berkeley, California 94720

J. J. Connell
Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637

Received 25 September 1997

The weak β+ decay of the astrophysically significant radioisotope 54Mn has been observed. The energies of positrons from a chemically purified 54Mn source were measured using the APEX spectrometer at Argonne National Laboratory. We deduce a β+ decay branch of (1.20±0.26)×10-9, corresponding to a partial half-life of (7.1±1.5)×108 yr. The implications of this value for cosmic-ray confinement times are discussed in light of recent satellite measurements of the cosmic-ray abundance of 54Mn.


©1998 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevLett.80.2085
DOI: 10.1103/PhysRevLett.80.2085
PACS: 23.40.Hc, 26.40.+r, 27.40.+z, 98.38.-j

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