Characterization and optimization of pyroelectric X-ray sources using Monte Carlo spectral models

Abstract

Pyroelectric X-ray sources produce emission through bulk heating of a ferroelectric crystal. In this study, a least-square based systematic curve fitting of X-ray emission to predicted models is used to generate an equivalent monoenergetic incident electron energy to simplify further X-ray source optimization. The measured X-ray spectrum of a 1cm3 lithium tantalite crystal cycled over 140K are shown to be approximated by those of an 85keV monoenergetic electron beam. Using monoenergetic electron sources, common configurations for transmission and directional X-ray sources are simulated using electron targets comprised of gold, silver, copper, molybdenum and tungsten. X-ray production efficiency depends on target material selection, incident electron energy, and target thickness for both transmission and reflection geometries. At 20keV, silver produced 69.7% more flux was in comparison to copper, the least efficient target material at this energy. Conversely, at 85keV copper outperformed silver, the least efficient target material at this energy, by 21.6%. Pyroelectric X-ray sources can be improved for flux and energy tuning through the use of modeling and target design. Continued development of pyroelectric X-ray sources can lead to wide scale implementation for industrial X-ray fluorescence and medical therapeutic applications.