Simulation of image formation using compound X-ray zone plates

In this paper, we consider the correlation between the resolution of a Fresnel zone plate and the width of its outermost zone. Obtaining an image of an X-ray source using multi-order zone plates is discussed. It is shown that the resolution of a conventional Fresnel zone plate can be improved by a factor of 10 by designing a compound zone plate with six operative orders, with the width of the outermost zone remaining unchanged. In this case, the efficiency of focusing the X-rays into an image is slightly less than 4 per cent. Note that the efficiency attained is 1.5 times that of a conventional third-order Fresnel zone plate. In addition, the resolution of the compound zone plate is 3.05 times that of a conventional second-order Fresnel zone plate.