X-ray fluorescence analysis with portable instruments

X-ray fluorescence (XRF) analysis with two portable instruments, a pyroelectric X-ray generator and a hand-held spectrometer, has been studied. The pyroelectric X-ray generator is a novel X-ray source that utilizes a charging phenomenon on a pyroelectric crystal to generate X-rays. This X-ray source has such characteristics as dry battery drive and periodically changing low X-ray output. The latter seems to be a disadvantage for XRF analysis. However, in the present study, the capability for elemental analysis at % level and the identification of many samples based on the spectral difference was demonstrated. Moreover, the capability for quantitative analysis at ppm level with a chelate extraction method or an ion-exchange method was proved. High sensitization of the analysis was achieved by using a disk-shaped secondary target with a hole in its center. Large solid angle X-rays emitted from this generator were effectively put to use by the straight-line arrangement of the X-ray generator, sample support, secondary target, and detector. With regard to the hand-held spectrometer, shielded objects were analyzed, and their composition could be estimated with an error of less than 30% by using the attenuation coefficient. This study presented new applications of portable spectrometers.