Versatile Monochromatic X-ray sources with Energy Tunability for Nuclear Security and Medical Applications

One of the most important components in any X-ray imaging and computed tomography system intended as a probe for detection and characterization of nuclear materials is the X-ray source. The source affects several important imaging parameters such as spatial and temporal coherence, emission energy, and photon flux. However, existing mobile or transportable X-ray sources in the form of X-ray tubes induce bremsstrahlung radiation that offers little to zero energy tunability or directionality capabilities. These limitations motivate research into new materials with the potential to create monochromatic X-ray sources with energy and angular tunability. Recent advances in van der Waals layered superlattice crystalline materials have been used to demonstrate new X-ray generation mechanisms such as parametric X-ray radiation and coherent bremsstrahlung that have the advantages of being tunable relative to existing sources. In this paper, we explore a wide range of superlattices and their characteristics to precisely tailor the X-ray spectrum and angular distribution. We show that by using inverse design techniques and material customization at the atomic level we can optimize the output radiation characteristics for different imaging scenarios.