RESUMO
A procedure is described for the non-destructive determination of Na, Mn, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu and Th in apatites by thermal and epithermal neutron-activation of independent portions of the material. The method was applied to three apatites with different contents. The precision obtained was better than +/-5% for La, Ce, Sm, Eu, Gd, Tb and Dy and +/-20% for Yb, Nd, Ho, Er and Lu for an apatite with a total rare-earth oxide content of the order of 1%. Determination of Ce, Tb and Yb could only be carried out with thermal neutron-activation analysis, while Gd, Ho and Er could only be determined after irradiation with epithermal neutrons.
RESUMO
A neutron-activation scheme designed for the determination of 42 elements in lunar rocks and fines is described. The scheme is based on seven different irradiations, four of which are followed by direct gamma-spectrometry, and three by radiochemical separation systems. The total sample consumption for duplicate analysis is about 800 mg. The scheme has been tested on basalt BCR-1, and results for this standard rock are presented. Analytical experience obtained from analyses of lunar samples and BCR-1 is discussed.
