Half-Lives ofMn52andMn54

Manganese activities produced by deuteron bombardment of chromium powder and radiochemically purified both by standard chemical techniques and ion-exchange chromatography, have been counted for a period of 2500 hr. The half-life of ${\mathrm{Mn}}^{54}$ is determined to be 291±1 days, while that of ${\mathrm{Mn}}^{52}$ is found to be 5.72±0.02 days.