Abstract
The weak decay of the astrophysically significant radioisotope has been observed. The energies of positrons from a chemically purified source were measured using the APEX spectrometer at Argonne National Laboratory. We deduce a decay branch of , corresponding to a partial half-life of . The implications of this value for cosmic-ray confinement times are discussed in light of recent satellite measurements of the cosmic-ray abundance of .
- Received 25 September 1997
DOI:https://doi.org/10.1103/PhysRevLett.80.2085
©1998 American Physical Society