Transmission type logarithmic spiral crystal analyzer for monochromatic X-ray imaging

On the basis of the conformal characteristics of a logarithmic spiral crystal in a large field of view(FOV),a new type of transmission crystal analyzer used for X-ray monochromatic imaging was investigated.Compared with a reflection type of crystal analyzer,the logarithmic spiral crystal analyzer has a wider FOV for catching the monochromatic X-ray image and a simple space arrangement for achieving the same magnification.According to the diffraction theory of the crystal and the surface equation of log spiral,the imaging principles and characteristics of the transmission type logarithmic spiral crystal analyzer were researched,including the magnifications in horizontal and vertical directions as well as the FOV sizes.A logarithmic spiral analyzer with a quartz crystal was developed.Then with the proposed analyzer,the monochromatic backlighting experiment for the mesh grid with a diameter of 100 μm was carried out by taking an X-ray source of Cu target as the backlighter.The experimental results show that the FOVs of the transmission type logarithmic spiral crystal analyzer are 15.938 7 mm and 5.900 6 mm in horizontal and vertical directions,respectively.Furthermore,the spatial resolution of the analyzer is at least 30 μm under a source diameter of 110 μm.