A direct comparison of a Si(Li) detector with a sphericaly bent crystal X-Ray spectrometer in trace element analysis

Abstract

A direct experimental comparison of a Si(Li) detector with a spherically bent crystal x-ray spectrometer for trace element analysis is presented. Characteristic x-rays are produced by electron bombardment of powder and aqueous-residue samples placed on the anode of a demountable x-ray tube. The resulting radiatmn is analyzed simultane- ously by each spectrometer. The data include the minimum detectable limit (b.: DL) in terms of percent concentration in a light element matrix for the powder samples and in terms of the mass of the element for re,ddue samples. MDLs obtained with the Si(Li) detector approach those obtained with the crystal spectrometer. However, the crystal spectrometer was found to be superior in analyzing complex spectra. A!though the electron excitation technique was not expected to haw any particular merit as an ana- lytical tool, traces as small as a few nanograms of some elements are easily detectable in residue samples.