Radioactive Decay ofDy159

Decay of ${\mathrm{Dy}}^{159}$ has been shown to feed three excited levels in ${\mathrm{Tb}}^{159}$. Gamma rays with energies of 58 kev, 200 kev, 290 kev, and 350 kev have been observed and electron-capture branching ratios have been determined. Only $L$ electron capture to the 350-kev level has been detected. The half-life of the 58-kev level in ${\mathrm{Tb}}^{159}$ has been shown to be less than 1×${10}^{-9\mathrm{}}$ sec. The $K$ conversion coefficient of the 58-kev gamma ray has been measured and found to be 5±1.5. The disintegration energy of ${\mathrm{Dy}}^{159}$ has been shown to lie between 360 and 400 kev; the half-life was remeasured and found to be 144.4±0.2 days.