The Dual Decay ofRe186

Abstract

The decay of ${\mathrm{Re}}^{186}$ (91 hr) has been investigated using spectrometer and coincidence methods. Two beta-groups with maximum energies of 1.070±0.005 Mev and 0.942±0.008 Mev have been observed. The lower energy beta-spectrum leads to an excited state in ${\mathrm{Os}}^{186}$ of 0.136-Mev energy. Nine percent of all disintegrations are by $K$-capture; two-thirds of which lead directly to the ground state of ${\mathrm{W}}^{186}$ and one-third to an excited state of 0.122-Mev energy. Evidence is given for a spin 1 and odd parity of the ground state of ${\mathrm{Re}}^{186}$. These assignments agree with the predictions of the one-particle spin-orbit coupling model extended to odd-odd nuclei.