New Lens‐Free X‐ray Source for Laboratory Nano‐CT with 50‐nm Spatial Resolution

X‐ray optics, such as zone plates, are often used to obtain a spatial resolution better than 100 nm in x‐ray projection images. Such types of optics are not always suited for tomographic imaging due to their limited depth of focus, which restricts the size of the specimen to a few microns. To overcome these limitations, we developed a new lens‐free setup for a nano‐CT system. Spatial resolution of nano‐CT systems is mainly defined by x‐ray source performance. It is dependent on target shape and focusing of the electron beam. The typical way to improve spatial resolution is based on replacement of the bulk metal target to thin film. It allows getting submicron spot size, but significantly reduces x‐ray flux. To overcome flux limitation without compromising with spatial resolution, we invented a new type of target shaped as a rod or needle towards the camera. It allows us to reach 50‐nm resolution with reasonable flux.