  The ever-increasing brightness of synchrotron radiation sources demands
improved x-ray optics to utilise their capability for imaging and probing
biological cells, nano-devices, and functional matter on the nanometre scale
with chemical sensitivity. Hard x-rays are ideal for high-resolution imaging
and spectroscopic applications due to their short wavelength, high penetrating
power, and chemical sensitivity. The penetrating power that makes x-rays useful
for imaging also makes focusing them technologically challenging. Recent
developments in layer deposition techniques that have enabled the fabrication
of a series of highly focusing x-ray lenses, known as wedged multi layer Laue
lenses. Improvements to the lens design and fabrication technique demands an
accurate, robust, in-situ and at-wavelength characterisation method. To this
end, we have developed a modified form of the speckle-tracking wavefront
metrology method, the ptychographic x-ray speckle tracking method, which is
capable of operating with highly divergent wavefields. A useful by-product of
this method, is that it also provides high-resolution and aberration-free
projection images of extended specimens. We report on three separate
experiments using this method, where we have resolved ray path angles to within
4 nano-radians with an imaging resolution of 45nm (full-period). This method
does not require a high degree of coherence, making it suitable for lab based
x-ray sources. Likewise it is robust to errors in the registered sample
positions making it suitable for x-ray free-electron laser facilities, where
beam pointing fluctuations can be problematic for wavefront metrology.
