The present invention relates to a method and a device for measuring scattering of X-rays wherein the compound to be analyzed is installed in a receptacle comprising an X-ray-permeable flat bottom, wherein the X-ray diffraction analysis is undertaken by sending an X-ray stream upwards toward said X-ray-permeable bottom and by measuring the stream of scattered X-rays reflected downwards, and wherein a fluid thermostatically controlled to the same temperature as that of the compound to be analyzed in the receptacle is projected toward the X-ray permeable flat bottom, from outside the receptacle.