The invention relates to a device for the delivery of a beam of X-rays for analysis of a sample (50), comprising: a source block (100) comprising X-ray emission means; an optical block (200) placed downstream of the source block (100), said optical block (200) comprising an optical monochromator component (210) having a reflecting surface (212) provided for conditioning X-rays emitted by the source block (100) according to unidimensional or bidimensional optical effect; and definition means (300) of X-rays comprising: an anti-diffusing member (310) for spatially delimiting X-rays conditioned by the optical monochromator component (210), placed downstream of the optical monochromator component (210) and comprising one or more plates (311) having portions (313) arranged to form a delimiting orifice (312), said portions (313) being coated with a monocrystalline material limiting the scattering of X-rays; a cut-off member (320) of X-rays emitted by the source block (100), comprising X-ray absorption means arranged in the delivery device to cut off the direct X-ray beams likely to reach the spatial delimitation anti-diffusing member (310) without conditioning by the optical monochromator component (210).