X-ray irradiation device for X-ray imaging, comprising spectrally shaped X-ray optical element and spectrally filtered aperture device

An X-ray irradiation device (100) comprises an X-ray source device (110) for generating X-rays (2) having a multicolor spectrum and an X-ray optics (120) having a longitudinal beam axis (3). Wherein the X-ray optics (120) comprise a polycrystalline reflector device (121) having a reflector geometry, a reflector tessellation, and a reflector thickness. The reflector device (121) is arranged for receiving a portion of the X-rays (2) within an acceptance angle of the reflector device (121) and for generating an X-ray beam (4) by Bragg reflection. The X-ray beam is directed along the beam axis (3) towards its focal position and has a spectral distribution determined by the polychromatic spectrum of the X-rays (2), the reflector geometry, the reflector tessellation and the reflector thickness. Wherein the X-ray irradiation device (100) further comprises spectral filtering aperture means (122), arranged downstream of the reflector means (121), for generating a filtering gap (123), which transmits a first spectral portion (4A) of the spectral distribution of the X-ray beam (4), and blocks a second spectral portion (4B) and a third spectral portion (4C) of the spectral distribution. Wherein the first spectral portion (4A) has a higher energy than the second spectral portion (4B) and a lower energy than the third spectral portion (4C). Wherein the reflector device (121) has a receiving solid angle of at least 100 microsphericity, and the reflector geometry, the reflector tessellation, the reflector thickness and the acceptance angle of the reflector device (121) are selected such that the radiation flux in the first spectral portion (4A) is at least 1% of the incident flux of the same spectral portion of the X-rays (2) received by the reflector device (121), the first spectral portion (4A) has a spectral bandwidth of at most 15%, the flux of the second and third spectral portions (4B, 4C) is reduced by at least three orders of magnitude compared to the flux of the first spectral portion (4A), and the second and third spectral portions (4B, 4C) have a peak reflectance of at least 1%. And the focal spot size of the X-ray beam (4) is less than 1.5 mm in both transverse dimensions with respect to the longitudinal beam axis. In addition, an X-ray fluorescence imaging device (200) and a method of using the X-ray irradiation device (100) are described.