In phase contrast imaging, an object is radiated with coherent X-ray radiation, for example achieved by placing a grating structure in front of a conventional X-ray tube. For example, WO 2011/070521 A1 relates to differential phase contrast imaging and describes a respective system. A grating in front of the focal spot is provided to enhance the coherence length of the generated X-rays to a useful level. The grating is required to have a transparency that is reduced due to the requirement of having a small slits-to-pitch ratio, for example for the benefit of improved detection of phase shifts. However, it has been shown that for achieving sufficient image data quality, X-ray tubes with increased tube power are needed, which can result in expensive tubes. An example for increasing X-ray tube power is the provision of liquid metal jets acting as the anode for generating the X-ray radiation. For example, U.S. Pat. No. 6,995,382 B2 describes an arrangement for generating intensive radiation based on plasma generation, where the target generator has a multiple channel nozzle with a plurality of target jets for the generation of intensive short wave radiation. The plasma generated from the target jets merge into one extended plasma, leading to a powerful light source. However, the generation of plasma reduces the suitability for phase contrast X-ray imaging. It must be noted further that a source grating would have to be provided, which means additional effort due to the necessary manufacturing steps for the grating. Further, since the X-ray absorbing portions may be provided by gold material which is becoming a more and more expensive material, this also implies negative economic effects.