The Radiations fromHf181

The beta-spectrum and photoelectron spectrum of ${\mathrm{Hf}}^{181}$ have been studied with a semicircular focusing beta-ray spectrograph of 2 percent resolving power. In addition to the continuous beta-spectrum, four partially converted gamma-rays were found. An estimate of the relative intensities of the two higher energy gamma-rays can be made from the Compton and photo-electron intensities. Data have also been obtained from $\beta -\gamma$- and $\beta -e^{-}$-coincidence measurements. An energy level diagram is discussed.