Phase-contrast x-ray microscopy with a point focus x-ray source

Phase-contrast x-ray microscopy has been performed using a point focus x-ray source. The method is essentially the projection microscopy, but the contrast enhancement due to the refraction is obtained by taking a certain sample-detector distance large enough to spatially resolve phase gradients in the x-ray beam. The spatial resolution was measured to be 2.5 μm in horizontal and 2.2 μm in vertical directions. A phase contrast image of a glass tube was taken, and the contrast enhancement was clearly observed in boundary regions. The phase contrast images of a butterfly and a mosquito were also taken. It was confirmed that this method was useful to observe samples composed of light elements such as insects.