High-energy x-ray production with pyroelectric crystals

The invention of pyroelectric x-ray generator technology has enabled researchers to develop ultraportable, low-power x-ray sources for use in imaging, materials analysis, and other applications. For many applications, the usefulness of an x-ray source is determined by its yield and endpoint energy. In x-ray fluorescence, for example, high-energy sources enable the excitation of the $K$-shell x-ray peaks for high-$Z$ materials as well as the lower-energy $L$-shell peaks, allowing more positive sample identification. This report shows how a paired-crystal pyroelectric source can be used to approximately double the endpoint x-ray energy, in addition to doubling the x-ray yield, versus a single-crystal source. As an example of the advantage of a paired-crystal system, we present a spectrum showing the fluorescence of the $K$ shell of thorium using a pyroelectric source, as well as a spectrum showing the fluorescence of the $K$ shell of lead. Also shown is an x-ray spectrum with an endpoint energy of 215 keV.