Determination of Rare Earth Elements in Cosmo-geological Samples Aided by Wavelength Dispersive X-ray Fluorescence Spectroscopy

Abstract

While rare earth elements are generally probed with destructive techniques such as LA-ICP-MS, this causes at least partial destruction of the sample, which is not desirable when precious materials such as cosmo-geological (return) samples are examined. With the proposed wavelength dispersive synchrotron radiation X-ray fluorescence spectroscopy technique the rare earth element characteristic L-lines, situated between 4.65 and 7.66 keV, can be qualitatively and quantitatively detected in a nondestructive manner in precious samples. The method is based on a sequential scanning θ-2θ geometrical setup making use of a flat Ge(111) analyzer crystal and a small energy dispersive detector, measuring the radiation in Bragg conditions. To optimize the solid angle of detection a polycapillary half-focusing lens was positioned between the sample and the crystal, collimating and guiding the radiation. Validation of the technique is provided by comparing the obtained quantitative results with previously obtained LA-ICP-MS results measured on the sample.