Single-grating Talbot imaging relies on high-spatial-resolution detectors to perform accurate measurements of X-ray beam wavefronts. The wavefront can be retrieved with a single image, and a typical measurement and data analysis can be performed in few seconds. These qualities make it an ideal tool for synchrotron beamline diagnostics and in-situ metrology. The wavefront measurement can be used both to obtain a phase contrast image of an object and to characterize an X-ray beam. In this work, we explore the concept in two cases: at-wavelength metrology of 2D parabolic beryllium lenses and a wavefront sensor using a diamond crystal beam splitter.
The current status of the software package PHASE for the propagation of coherent light pulses along a synchrotron
radiation beamline is presented. PHASE is based on an asymptotic expansion of the Fresnel-Kirchhoff integral
(stationary phase approximation) which is usually truncated at the 2nd order. The limits of this approximation as well as
possible extensions to higher orders are discussed. The accuracy is benchmarked against a direct integration of the
Fresnel-Kirchhoff integral. Long range slope errors of optical elements can be included by means of 8th order
polynomials in the optical element coordinates w and l. Only recently, a method for the description of short range slope
errors has been implemented. The accuracy of this method is evaluated and examples for realistic slope errors are given.
PHASE can be run either from a built-in graphical user interface or from any script language. The latter method provides
substantial flexibility. Optical elements including apertures can be combined. Complete wave packages can be
propagated, as well. Fourier propagators are included in the package, thus, the user may choose between a variety of
propagators. Several means to speed up the computation time were tested - among them are the parallelization in a multi
core environment and the parallelization on a cluster.