Design study for a compact laser-driven source for medical x-ray fluorescence imaging

Abstract

Thomson scattering sources with their hard x-ray pencil beams represent a promising candidate to drive high-resolution X-ray Fluorescence Imaging (XFI). As XFI is a scanning imaging modality, it specifically requires pencil-beam geometries along with a high beam mobility. In combination with laser-wakefield acceleration (LWFA) such sources could provide the compactness needed for a future transition into clinical application. A sufficient flux within a small bandwidth could enable in-vivo high-sensitivity XFI for early cancer diagnostics and pharmacokinetic imaging. We thus report on a specific all-laser driven source design directed at increasing the photon number within the bandwidth and opening angle defined by XFI conditions. Typical parameters of driver lasers and electron bunches from LWFA are utilized and controlled within realistic parameter regions on the basis of appropriate beam optics. An active plasma lens is implemented for chromatic focal control of the bunch. Source performance limits are identified and compared to existing x-ray sources with regard to their potential to be implemented in future clinical XFI.