We present a new interactive framework package for coherent and partially coherent X-ray wavefront propagation simulations – “WaveProperGator” (WPG). The package has been developed at European XFEL to facilitate for the end users (beamline scientists and XFEL users) the designing, optimizing and improving X-ray optics to meet their experimental requirements. Our package uses SRW C/C++ library and its Python binding for wavefront propagation simulations. The tool allows for changing source and optics parameters and visualizing the results interactively. The framework is cross-platform: it runs reliably on Linux, MS Windows 7, and Mac OS X. Several application examples, specific for XFEL, will be presented.

A new graphic environment to drive X-ray optics simulation packages such as SHADOW and SRW is proposed. The aim is to simulate a virtual experiment, including the description of the electron beam and simulate the emitted radiation, the optics, the scattering by the sample and radiation detection. Python is chosen as common interaction language. The ingredients of the new application, a glossary of variables for optical component, the selection of visualization tools, and the integration of all these components in a high level workflow environment built on ORANGE are presented.

The ultrahigh energy resolution IXS spectrometer being developed at the National Synchrotron Light Source II (NSLS-II) employs an innovative optical design. Its analyzer system utilizes an L-shaped laterally graded multilayer mirror in tandem with a multi-crystal arrangement. The multi-crystal arrangement explores extremely asymmetric Bragg reflections to achieve sub-meV energy resolution. The L-shaped laterally graded multilayer mirror was designed to increase the angular acceptance of the multi-crystal optics, i.e. it performs angular collimation of the incoming beam. Here we present simulations of the mirror performance and positioning and stability requirements in conjunction with the multi-crystal energy analyzer.

Improved modeling of coherent and partially-coherent x-ray generation, transport, interaction and detection is essential for designers and users of experiments at state-of-the-art light sources, including low-emittance storage rings, energy-recovery linacs and free-electron lasers. This requires accurate physical models for a variety of emission processes, the structures of x-ray optical elements, interaction with many types of samples, and propagation of scattered photons to a detector of arbitrary geometry. We present the status of an open simulation framework, including a graphical user interface, which will facilitate start-to-end simulations by a number of independent codes, with support for broad community involvement.

A grid-based technique was investigated, based on the demonstration by Bennett et al, [Med Phys 37 6047]. Images were taken with 50W Rh source and focused mammography grids of 200-300 µm periods using a camera of 22 µm pixels. Phase information was extracted from a single raw image by comparing windowed regions centered on grating harmonics in the Fourier domain. The central harmonic attenuated by absorption while the higher harmonics contain absorption as well as small angle diffraction. The effects of varying grid, object, detector distances, and width of the Gaussian window were investigated.

Much progress has been made during the last several decades in understanding the physics and in developing modelling of generation and transport of the x-ray beams. From the third generation undulator sources, more advanced x-ray sources are and will be operating in the future, such as the undulator radiation from ultimate storage rings, XFELs, and XFEL oscillators. For advanced x-ray utilization, optimization of the x-ray beamline configuration is as important as the production of high-coherence x-rays. The issues in beamline modeling include effect of mirror roughness, aberration from the grazing incidence geometry, change of the polarization state, etc. In the future, the demand on the precision and efficiency of the modelling will become more challenging to keep up with the anticipated stringent user specifications for next generation of applications. After an overview of the current status in the x-ray production and transport, we will attempt to project the future development in these areas.

Hard X-ray undulator radiation at 3rd generation storage rings falls between the geometrical and the fully coherent limit and cannot be completely modeled by incoherent ray tracing or by fully coherent wave propagation. In addition, X-ray optics such as mirrors introduce unavoidable distortions on the wavefront. We have used the the wavefront propagation code Synchrotron Radiation Workshop (SRW) running in a Python environment to model partial coherence. We have also modeled distortion of the wavefront using measured surface errors on the mirrors.

European X-ray Free Electron Laser (XFEL) will deliver the X-ray femtosecond pulses with high repetition rate up to 4.5MHz and be most powerful in comparison with existing facilities. Many factors impose strict requirements on XFEL optics: full transverse coherence, large apertures, wide photon energy ranges, 3-25keV and 0.25-3.5keV for hard and soft X-rays, varying divergence. For proper design, full-scale wavefront simulations, with taking into account optics imperfectness and diffraction effects are required. Application examples for various focusing optics schemes at European XFEL will be presented. Status of framework for start-to-end simulation for single particle imaging experiments will be also discussed.

The challenging in-place ESRF Upgrade Programme Phase I foresees the reconstruction of about one third of the beamlines. The new beamlines will be very long (more than 100 m) to use routinely micro- and nano-beams. This requires a very high demagnification of the ESRF source, which makes beamline optics design a fundamental concept for the future availability of bright and small beam. In the design of these beamlines an intense use of computer tools for x-ray optics is necessary. Ray-tracing has demonstrated to be a very reliable tool for designing and optimizing synchrotron beamlines. A substantial effort has been invested at the modernizing the SHADOW package and facilitating its use. Some examples of recent simulations for Upgrade beamlines will be presented, including simulations for refractive optics (CRL and transfocators), bent crystals and graded multilayers. In parallel, an ambitious project for the upgrade and integration of existing software and development of new toolbox will be discussed, with particular interest in beam polarization and partial coherence.

As experimental concept and execution becomes increasingly complex at current generation x-ray sources, data analysis becomes more complicated and the urgency of completing an experiment on the first attempt grows. It has become apparent that simulation of the expected signal from such experiments can increase the likelihood of success on the "first try" and increase the efficiency of a facility as a whole. Here, we discuss a modular approach to the simulation problem under development at SLAC, which will build on existing expertise and software.

Recent updates in the “Synchrotron Radiation Workshop” wave-optics computer code, including the results of collaborative development efforts in the area of X-ray optics and in other areas, as well as some simulation activities for storage ring beamlines and X-ray FEL instruments, will be reported. Future development plans will be described.

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 which is usually terminated at the 2nd order (stationary phase approximation). The limits of this approximation as well as possible extensions to higher orders are discussed. PHASE can be run from any script language which provides substantial flexibility. Slope errors or apertures can easily be realized and wave packages can be propagated as well. Code parallelization on a multi core mashine was tested successfully.

We present an open source python based ray tracing tool that offers several useful features in: graphical presentation, material properties, implementation of diffractive and refractive elements, complex (also closed) surfaces, multiprocessing and portability. We exemplify the present version by modeling (i) a curved crystal analyzer, (ii) a quarter wave plate, (iii) Bragg-Fresnel optics and (iv) multiple reflective and non-sequential optics (polycapillary). We also present the latest development: (a) in implementation of OpenCL framework for calculations on CPUs and GPUs and (b) in calculating the Kirchhoff integral that is used for the reconstruction of wave fronts and calculation of grating efficiencies.

We present examples of applying the X-ray tracing software package McXtrace to X-ray scattering experiments, focusing on time-resolved type experiments at FEL facilities, where beamtime is scarce and experiments tend to be complicated. As an example, consider a pump-and-probe type experiment: To get the wanted signal from the sample, the probing X-ray pulse needs to overlap in space and time with the pumping pulse inside the sample. This is made more difficult by several effects, such as beam jitter, non-uniform sample-beam interactions, polarization dependence etc. We will present studies of such experiments along with the newest McXtrace developments.

MASH allows to run a set of ray-tracing simulations, e.g. over a range of photon energies, fully automatically. Important output parameters, such as photon flux, photon irradiance, focal spot size, bandwidth, etc. are then directly provided as function of photon energy. Apart from photon energy any parameter or set of parameters can be scanned through as well. Heat load calculations with finite element analysis (Comsol) providing temperatures, stress and deformations are fully integrated. The deformations can be fed back into the ray-tracing process simply by activating a switch.

We have attempted to boost the performance of the python based ray tracing package xrt by shifting the most time consuming operations to the GPU invoking the PyOpenCL extension. Up to 100x performance gain is observed for the operations characterized by high computational load and low intensity of device-host memory exchange. Among these we can stress numerous integration tasks during the undulator flux density distribution calculation, derivation of the ray-surface intersection point at each optical element in the beam path, tracing the propagation of rays in thick/deformed crystals within the framework of the dynamic diffraction theory.

We demonstrate the limitations of specification and performance evaluation of X-ray optics based on the totally statistical approach, including rms roughness and residual slope variation, and power spectral density distribution. The limitations are fatal, especially, in the case of highly coherent x-ray beams. As a way to overcome the problem, we treat autoregressive-moving-average modeling of metrology data [Opt. Eng. 51(4), 046501, 2012]. The effectiveness of the approach is demonstrated with a number of examples peculiar to the X-ray optical systems under design at the European FEL. Supported by the U. S. Department of Energy under contract number DE- AC02-05CH11231.

We report on the implications of a design of the Soft Matter Interfaces (SMI) beamline, a long energy range canted in-vacuum undulator (IVU) beamline at NSLS-II, based on geometrical ray-tracing and partially coherent x-ray beam wavefront propagation simulation software packages, namely, SHADOW and SRW. We compare the resulting complete beamline simulations performed with both software packages. We stress that the neglect of the wave-optics effects in geometrical ray-tracing approach results in significant discrepancies in beam spot size, beam shape and the angular divergences which is crucial in determining the future performance of an instrument.

Up to now simulation of perfect crystals optics in the Synchrotron Radiation Workshop (SRW) was not available. Thus, accurate modelling of synchrotron beamlines containing multiple-crystal arrangements was hindered. A new SRW module for calculating dynamical diffraction from a perfect crystal in the Bragg case overcomes this shortage. It was successfully applied to model synchrotron radiation propagation through the Inelastic X-ray Scattering (IXS) Beamline at the NSLS-II. The IXS experiments are usually photon-hungry. Accurate evaluation of the photon flux at a sample position is imperative. Here, the results of the simulation are presented and compared with those of other codes.

Ray-tracing algorithms are used to simulate the instrumental function of a synchrotron beamline targeted to the advanced characterization of nanocrystalline materials by powder diffraction. The characteristics of the source, a bending magnet in the present case of study, and the optics influence the instrumental profile, which is a key parameter for obtaining information on the nanostructure. We combine the SHADOW simulation with the calculation of powder diffraction profiles from standard materials, into a high-level workflow environment based on the ORANGE software, allowing us to integrate data analysis fitting software with realistic information.

A dream x-ray spectrometer is a spectrograph that images x-ray spectra in a single shot with required spectral resolution. Spectrograph is an optical device that disperses photons of different energies into distinct directions and space locations, and takes a snapshot of photons spectra with a spatially sensitive photon detector. Feasibility of hard x-ray spectrographs with a spectral resolution as small as 0.1 meV has been demonstrated recently [1]. Here we present a theory of hard x-ray spectrographs consisting of collimating, angular dispersive, and focusing optics. Single crystal arrangements in asymmetric scattering geometry are used as dispersing elements. Ray transfer matrix technique is applied to propagate x-rays through the optics elements. Several designs of hard x-ray spectrographs with an energy resolution of 1-0.1 meV and a spectral window of 100-10 meV are proposed and analyzed using the theory.\\ 1. Yu. Shvyd'ko, S. Stoupin, K. Mundboth, and J.-H. Kim "Hard-x-ray spectrographs with resolution beyond 100 micro-eV" Phys. Rev. A, 87, (2013) 043835

Until now, a treatment of dynamical diffraction from perfect crystals has been missing in the wavefront propagation computer code “Synchrotron Radiation Workshop” (SRW) despite the widespread use of crystals on X-ray synchrotron beamlines. Now a C++ module for calculating dynamical diffraction from a perfect crystal in the Bragg case has been written and integrated into the SRW C/C++ library. The code, now executable through SRW’s Python interface, has been benchmarked by comparison with predictions made by plane-wave and spherical-wave dynamical diffraction theory. Test simulations for a selection of X-ray synchrotron beamlines are also shown.

1D spatially resolved high resolution x-ray spectroscopy with spherical crystals and 2D detectors is used world wide on magnetic confinement fusion experiments for Doppler measurements of spatial profiles of plasma ion temperature and flow velocity. It is being developed for diagnosis of High Energy Density Physics plasmas at laser-plasma facilities and synchrotrons/x-ray FELs. Micron scale resolution with x-ray CCDs requires magnification, which is available with a von-Hamos like spectrometer using spherical crystals; instruments are being tested with a tungsten-target microfocus x-ray tube and x-ray CCD. Spatial resolution <10 μm and high spectral resolution have been demonstrated.

The method of calculating the transmission of hard x-ray radiation through a perfect and well oriented photonic crystal and propagation of x-ray beam modified by photonic crystal in the free space is developed. The method is based on the approximate solution of the paraxial equation at short distances, from which the recurrent formula for x-ray propagation at longer distances is derived. A computer program for numerical simulation of images of photonic crystals at distances just beyond the crystal up to several millimeters was created. The calculations were performed for Ni inverted photonic crystals with the [111] axis of the face cubic centered structure for the distances up to 0.4 mm with the step of 4 microns. Since the transverse periods of x-ray wave modulation are of several hundred nanometers, the intensity distribution of such a wave is changed significantly on the distance of several microns. This effect is investigated for the first time.

Monochromatic x-ray beams improve image contrast but suffer from low intensity if produced with a flat monochromator crystal. A doubly-curved crystal makes more efficient use of the source. However, the beam shape is not conducive to imaging. A combination of a bent crystal followed by a polycapillary optic can be used to monochromatize and focus x rays to a small spot to perform monochromatic x-ray imaging with good resolution. A ray-tracing simulation has been developed which accounts for defects in both optics types. Comparison was made to measurements of focal spot sizes, angular divergence, and image quality parameters including resolution and contrast

A goal of X-ray imaging is to obtain information about an object’s properties from intensity variations across a detector. In conventional radiography, the object’s ability to attenuate the primary beam is measured. However many materials of interest exhibit similar attenuation. In such cases, phase imaging can provide additional information to discriminate these materials. However, phase imaging generally requires significant computational effort to retrieve phase from intensity images. An overview of phase contrast mechanisms is discussed for several phase imaging modalities, including propagation-based and grid-based imaging, as well as computational techniques to recover phase from measured intensity information.

We demonstrate a quantitative X-ray phase contrast imaging technique derived from propagation based retrieval. In this method, the absorption and phase components are assumed to be correlated, and the transport of intensity equation is solved. The experimental setup is simple; the only requirements are a micro-focus X-ray source of sufficient temporal coherence and an X-ray detector of sufficient spatial resolution. This method was demonstrated in three scenarios: projection imaging index matched spheres, differentiating liquid samples, and computed tomography of a biological artery specimen. In all cases, the signal-to-noise ratio of phase contrast is greatly enhanced relative to conventional attenuation-based imaging.

Phase offers valuable information for medical and security applications where absorption alone is insufficient. We present an analytical method for simultaneously retrieving phase and absorption using images obtained from X-ray exposures at two different energies. Our approach takes advantage of the change in diffraction pattern associated with the change in wavelength. We demonstrate this approach experimentally using a micro-focus source and show that the retrieved phase is quantitative. We further implement this technique in tomography by imaging a biological sample with both phase and attenuation elements to show independent retrieval of absorption and phase.

Existing Computed Tomography (CT) systems require full 360 rotation projections. Using the principles of lightfield imaging, only 4 projections under ideal conditions can be sufficient when the object is illuminated with multiple-point X-ray sources. The concept was presented in a previous work with synthetically sampled data from a synthetic phantom. This current work presents the calibration procedure using a physical 3D phantom consisting of simple geometric shapes and the determination of minimal sampling parameters to achieve a targeted reconstruction resolution using ART. The results are compared with conventional CT scanning performed on the same phantom with the same apparatus.

The present paper reviews the X-ray grating imaging systems at home and abroad from the aspects of technological characterizations and the newest researching focus. First, not only the imaging principles and the frameworks of the typical X-ray grating imaging system based on Talbot-Lau interferometry method, but also the algorithms of retrieving the signals of attenuation, refraction and small-angle scattering are introduced. Second, the system optimizing methods are discussed, which involves mainly the relaxing the requirement of high positioning resolution and strict circumstances for gratings and designing large field of view with high resolution. Third, two and four-dimensional grating-based X-ray imaging techniques are introduced. Moreover, the trends of X-ray grating based imaging technology are discussed, especially the multiple information fusions are tried with attenuation, refraction and scattering obtained synchronously.