Coherent X-ray diffraction imaging and ptychography can be used to produce high resolution images of crystalline or noncrystalline samples. We have used this technique to investigate the crystal structure of single nanowires. At the 3rd generation synchrotron light source MAX IV in Lund, Sweden, we can get a highly coherent light beam that is ideal for pushing the limits of resolution for X-ray imaging.
In Bragg ptychography, a coherent light beam is directed to a sample which will attenuate and scatter the beam. For a crystalline sample the scattered beam will interfere constructively and give intensity peaks when the Bragg condition is fulfilled. These peaks are sampled with a pixelated detector in Bragg geometry. The data analysis from a X-ray Bragg ptychography experiment involves retrieving the phase from the measured amplitudes of the scattered beam, a procedure called phase retrieval. For this analysis we used the python package 'ptypy'. Initial analysis and testing of the software has been performed, without parallelization, in small scale on a laptop computer with good results.