Disintegration ofTa180

The modes of decay of 8-hour ${\mathrm{Ta}}^{180}$ have been studied by means of a magnetic spectrometer and coincidence-absorption techniques. It is found that approximately 21 percent of the decays involve either of two negative beta-particles in transitions to states of ${\mathrm{W}}^{180}$. The remainder of the decays proceed by means of $K$-capture to at least two different states of ${\mathrm{Hf}}^{180}$. No positrons are observed. Very prominent conversion lines attributed to a 93-kev gamma-transition in ${\mathrm{Hf}}^{180}$ are observed, in addition to a weaker line considered to be associated with a 102-kev gamma-ray in ${\mathrm{W}}^{180}$. Auger electrons are also present. The multipolarity of the 93-kev gamma-ray is thought to be electric quadrupole.