Apparatus and method of generating X-rays, in particular for X-ray fluorescence imaging , Vorrichtung und Verfahren zur Erzeugung von Röntgenstrahlung, insbesondere für die Röntgenfluoreszenzbildgebung

An X-ray source apparatus (100) for generating an X-ray beam (1), comprises a laser-plasma accelerator (10), which includes a gas channel (12) with an acceleration section for flowing a working gas along a flow direction, wherein the laser-plasma accelerator (10) is configured for irradiating a first pulsed laser beam (2) into the working gas, so that a plasma can be created in the working gas and an accelerated electron beam (4) can be generated, and a Thomson scattering part (20), which is configured such that the X-ray beam (1) can be generated by Thomson scattering of the electron beam (4) with a second pulsed laser beam (5), wherein the gas channel (12) includes a beam forming section for creating a pressure gradient so that the working gas flowing along the flow direction is subjected to a gas density reduction, wherein the pressure gradient is formed such that the transverse emittance of the electron beam (4) is preserved and, due to an adiabatic variation of transverse focusing forces in the plasma channel, the divergence of the electron beam (4) is reduced in the beam forming section relative to the acceleration section. Furthermore, an X-ray fluorescence imaging device including the X-ray source apparatus (100) and method for generating an X-ray beam (1) and for X-ray fluorescence imaging are described.