In these novel methods the image contrast is not based on X-ray absorption, but on their phase shift and ultra-small-angle scattering. X-ray phase contrast images are especially useful for light materials which show little X-ray absorption contrast. Darkfield or scattering images are beneficial for highly structured fabrics like fibre reinforced plastics, paper, textiles or very porous materials, where structural elements down to 1 µm can be detected.
Empa has two grating based systems available which allow for a simultaneous acquisition of a differential phase image, a dark-field or scattering image and the classical absorption image. These setups can be used for single radiographies or in CT mode. In addition Empa offers expertise and a vast network for lab- and synchrotron based free space propagation or coded aperture phase measurement methods.
Phase Contrast and Dark-Field Imaging Systems:
X-ray Talbot-Lau interferometer for phase-contrast and scattering imaging with a macro-focus source for fast image acquisitions:
X-ray Talbot-Lau based on a micro-focus CT setup: