Compact System for High Resolution X-ray Transmission Radiography, In-line Phase Enhanced Imaging and Micro CT of Biological Samples

Phase imaging visualizes phase shift of photons which passed the sample. Although phase sensitive X-ray imaging offers many advantages it is not routinely used in biological research due to demands of high intensity and highly coherent X-ray beam which is accessible mainly at synchrotron facilities. Phase sensitive imaging can be also carried out with microfocus X-ray tubes. However, the low beam intensity of such systems prolongs the exposure time to such an extent that common digital imaging detectors (CCD, Flat panels) are insufficient due to low efficiency, dark current and noise. This contribution presents a compact phase contrast enhanced imaging system based on a microfocus X-ray tube and the single photon counting pixel detector Medipix2. The spectral sensitivity of the detector together with the polychromatic nature of the beam allows distinguishing an absorption image from a phase image. Spatial resolution of the system can be on the sub micrometer level and measuring times less than a minute. Applications of the system for biological samples are presented. The simplicity of the system allows for routine laboratory work including dynamic in-vivo studies.