Determination of Lanthanum, Samarium and Europium in Manganese Nodules by Neutron Activation

The gamma spectrometric method has been developed for simultaneous determination of microgram amounts of lanthanum, samarium and europium without chemical separation of each other. The method was based on the chemical separation of rare earth mixtures from neutron irradiated samples and subsequent γ-ray scintillation counting of the isolated rare earth fractions. The sample was irradiated for 2∼3 days, 5 hr. each day, in the nuclear reactor JRR-1 at a flux of the order of 1011n/cm2/sec. The rare earth mixture purified by lanthanum fluoride cycles was used for γ-ray counting at a given pulse height peak. The activity of each component could be evaluated by resolving the decay curves obtained, and the amount calculated by comparing the activity with that of each monitor.