This PDF file contains the front matter associated with SPIE Proceedings Volume 10388, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

X-ray free electron lasers and next generation synchrotron radiation facilities will use larger and faster x-ray imaging detectors. We would like to introduce the present status and future perspective of the data acquisition and handling system, including the development program of the new generation image sensor, ongoing at SACLA/SPring-8 facilities.

Advanced analysis and modelling methods has been an essential part of X-ray optics advances and X-ray techniques development at synchrotron light sources. These methods not only help researchers develop designs of X-ray sources and beamlines, diagnose and identify problems and issues in operations, but also enable advanced modelling and simulations of novel X-ray optics and experiments. Recent development rends in diffraction-limited sources and in coherence applications further illustrate the community interests and increased needs in advanced wavefront-based analysis and modelling capabilities. This presentation will provide an overview of this growing area of X-ray optics and techniques and its impact on synchrotron science in general.

SPECTRA is a computer program to numerically characterize synchrotron radiation (SR) emitted from an electron beam passing through various SR sources, i.e., undulators, wigglers and bending magnets. Computations of SR with an arbitrary magnetic field distribution are also available. Parameters to specify the electron beam and SR source can be completely edited in graphical user interfaces (GUIs), and the computation results can be visualized graphically. Since the first release in 2001, SPECTRA has been used by many users worldwide, and implemented lots of new functions to adapt to the increasing diversity of applications using SR. In this paper, recent progress of SPECTRA is presented, mainly focusing on the new functions recently implemented.

The paper presents an overview of the main functions and new application examples of the “Synchrotron Radiation Workshop” (SRW) code. SRW supports high-accuracy calculations of different types of synchrotron radiation, and simulations of propagation of fully-coherent radiation wavefronts, partially-coherent radiation from a finite-emittance electron beam of a storage ring source, and time-/frequency-dependent radiation pulses of a free-electron laser, through X-ray optical elements of a beamline. An extended library of physical-optics “propagators” for different types of reflective, refractive and diffractive X-ray optics with its typical imperfections, implemented in SRW, enable simulation of practically any X-ray beamline in a modern light source facility. The high accuracy of calculation methods used in SRW allows for multiple applications of this code, not only in the area of development of instruments and beamlines for new light source facilities, but also in areas such as electron beam diagnostics, commissioning and performance benchmarking of insertion devices and individual X-ray optical elements of beamlines. Applications of SRW in these areas, facilitating development and advanced commissioning of beamlines at the National Synchrotron Light Source II (NSLS-II), are described.

Xrt is a python-based software library for beamline simulation and analysis in x-ray regime. We provide classes for many beamline elements, propagation engine in ray and wave approximations with full account for shapes and material properties, and high quality visualization capabilities. Recently added support for the GPGPU calculations via OpenCL not only allowed us to speed up the existing ray tracing routines but to qualitatively extend the limits of the theoretical models involved at all stages. As an example for the sources: we managed to increase the integration precision at high magnetic fields and high energies, which allows to calculate wigglers as undulators, an important case for the next-generation low-emittance synchrotrons. For the optics: wave propagation is implemented in the most general Kirchhoff integral form, therefore diffraction efficiency can be derived for multiple diffraction orders in gratings and zone plates. For the materials: reflectivity curves are calculated for the deformed crystals by solving the Takagi-Taupin equations numerically for each photon in the beam. We also introduce an XML-based file format to store the ray tracing project parameters and an interactive GUI tool, xrtQook, which we recommend for the project configuration editing and automatic ray tracing script generation.

In the next years most of the major synchrotron radiation facilities around the world will upgrade to 4th-generation Diffraction Limited Storage Rings using multi-bend-achromat technology. Moreover, several Free Electron Lasers are ready-to-go or in phase of completion. These events represent a huge challenge for the optics physicists responsible of designing and calculating optical systems capable to exploit the revolutionary characteristics of the new photon beams. Reliable and robust beamline design is nowadays based on sophisticated computer simulations only possible by lumping together different simulation tools. The OASYS (OrAnge SYnchrotron Suite) suite drives several simulation tools providing new mechanisms of interoperability and communication within the same software environment. OASYS has been successfully used during the conceptual design of many beamline and optical designs for the ESRF and Elettra- Sincrotrone Trieste upgrades. Some examples are presented showing comparisons and benchmarking of simulations against calculated and experimental data.

This paper presents details on some of the important new features in the newly released version of the x-ray tracing software package McXtrace. Although many developments have been made, this presentation is focused on the features that were required to meet the challenges posed for accurate simulation of the DanMAX beamline - a beamline currently under design at the MAX IV synchrotron. Among these may be mentioned: new source-models, new monochromator crystal models, multilayer capabilities, and the full beamline simulation frame itself.

Development of X-ray Free Electron Lasers (XFEL) opens new era in X-ray science. The full exploitation of unique properties of the XFEL radiation require challenging solutions that preserves radiation properties from a coherent, diffraction limited source under unprecedented instantaneous and average power load. We will present properties of simulated XFEL radiation such as coherence, source shape, divergence and longitudinal location inside the undulator. Recently, a construction of the LCLS II project has started as a major upgrade to the LCLS facility that will increase the average power of the XFEL up to 1 kW level. We will show how the X-ray simulations are used for minimizing thermal distortions on focusing of the LCLS II X-ray beams by 1 meter long Kirkpatrick-Baez mirrors. We will discuss and compare accuracy of simulations using different simulation methods and packages applied to focusing optics. The design of instruments should mitigate the damage to the optics caused by the tremendous instantaneous XFEL power. We will present X-ray simulation of the damage to the diffraction grating coatings and compare it with experimental results obtained at LCLS. The self-seeded mode of the LCLS operation increases temporal coherence and reduces greatly the bandwidth of the X-ray radiation. The results of time dependent X-ray simulations of the LCLS radiation passing through the seeding monochromator will be presented. We will compare two different approaches: Fourier Optics and an approach based on a dispersive system described by 6x6 pulse ray matrixes.

The upgrade of the Advanced Photon Source (APS) to a Multi-Bend Achromat (MBA) will increase the brightness of the APS by between two and three orders of magnitude. The APS upgrade (APS-U) project includes a list of feature beamlines that will take full advantage of the new machine. Many of the existing beamlines will be also upgraded to profit from this significant machine enhancement. Optics simulations are essential in the design and optimization of these new and existing beamlines. In this contribution, the simulation tools used and developed at APS, ranging from analytical to numerical methods, are summarized. Three general optical layouts are compared in terms of their coherence control and focusing capabilities. The concept of zoom optics, where two sets of focusing elements (e.g., CRLs and KB mirrors) are used to provide variable beam sizes at a fixed focal plane, is optimized analytically. The effects of figure errors on the vertical spot size and on the local coherence along the vertical direction of the optimized design are investigated.

The soft X-ray beamline IPE is one of the first phase SIRIUS beamlines at the LNLS, Brazil. Divided into two branches, IPE is designed to perform ambient pressure X-ray photo-electron spectroscopy (AP-XPS) and high resolution resonant inelastic X-ray scattering (RIXS) for samples in operando/environmental conditions inside cells and liquid jets. The aim is to maximize the photon flux in the energy range 200-1400 eV generated by an elliptically polarizing undulator source (EPU) and focus it to a 1 μm vertical spot size at the RIXS station and 10 μm at the AP-XPS station. In order to achieve the required resolving power (40.000 at 930 eV) for RIXS both the dispersion properties of the plane grating monochromator (PGM) and the thermal deformation of the optical elements need special attention. The grating parameters were optimized with the REFLEC code to maximize the efficiency at the required resolution. Thermal deformation of the PGM plane mirror limits the possible range of cff parameters depending of the photon energy used. Hence, resolution of the PGM and thermal deformation effects define the boundary conditions of the optical concept and the simulations of the IPE beamline. We compare simulations performed by geometrical ray-tracing (SHADOW) and wave front propagation (SRW) and show that wave front diffraction effects (apertures, optical surface error profiles) has a small effect on the beam spot size and shape.

We will discuss the optical design for a proposed beamline at NSLS-II, a late-third generation storage ring source, designed to exploit the spatial coherence of the X-rays to extract high-resolution spatial information from ordered and disordered materials through Coherent Diffractive Imaging, executed in the Bragg- and forward-scattering geometries. This technique offers a powerful tool to image sub-10 nm spatial features and, within ordered materials, sub-Angstrom mapping of deformation fields. Driven by the opportunity to apply CDI to a wide range of samples, with sizes ranging from sub-micron to tens-of-microns, two optical designs have been proposed and simulated under a wide variety of optical configurations using the software package Synchrotron Radiation Workshop. The designs, their goals, and the results of the simulation, including NSLS-II ring and undulator source parameters, of the beamline performance as a function of its variable optical components is described.

Mirrors operating at grazing angles utilising total external reflection are commonly used for focusing X-ray at synchrotron radiation sources. Figure error on the mirror causes distortion of the focus profile. We have modeled a well characterized test mirror which has three different modifications of the elliptical figure laid down in parallel lanes running the length of the mirror. The focusing of the mirror was simulated using geometric optics (ray tracing) and physical optics (wave propagation). The mirror was then tested with X-rays on a beamline at a synchrotron radiation facility. The comparison between the two simulation methods and the measured data elucidates the origins of structures on the intensity profile of the focused beam and demonstrate that for quantitative agreement between simulation and experiment, interference and diffraction effects must be modeled.

We continue to develop MOI method to analyze the mutual optical intensity (MOI) propagation through non-ideal optics. Local stationary phase approximation is implemented to calculate the MOI propagating through a non-ideal mirror. The phase generated by the path length from the incident to exit plane is the key to solve the MOI propagation through the mirror. The effect of figure error can be expressed as phase shift. There are two methods to deal with the figure error, the analytical method and numerical one. The two methods are compared at different spatial frequency range of the figure error. An APS beamline is analyzed with the developed MOI model, in which a partially coherent beam with 10keV energy is focused to ~20nm by a non-ideal elliptical mirror. The MOI at the focal plane is acquired after propagation through the non-ideal mirror. The intensity profile, the wavefront and the global coherence degree can be get from the MOI. The results indicate that the figure error with low spatial frequency generates oscillations, redistributes coherence property and damages the wavefront on the image plane. However, the figure error does not change the global coherence degree. Comparison with other codes such as Hybrid and SRW was performed. The results show that MOI model and SRW have similar intensity profiles. The apparent oscillations from MOI model and SRW indicate high coherence. Limitation on the beam size by the BDA and mirror will increase the coherence, which can be quantitatively analyzed by global coherence degree from MOI.

To achieve high resolution and sensitivity on the nanometer scale, further development of X-ray optics is required. Although ex-situ metrology provides valuable information about X-ray optics, the ultimate performance of X-ray optics is critically dependent on the exact nature of the working conditions. Therefore, it is equally important to perform in-situ metrology at the optics’ operating wavelength (‘at-wavelength’ metrology) to optimize the performance of X-ray optics and correct and minimize the collective distortions of the upstream beamline optics, e.g. monochromator, windows, etc. Speckle-based technique has been implemented and further improved at Diamond Light Source. We have demonstrated that the angular sensitivity for measuring the slope error of an optical surface can reach an accuracy of two nanoradians. The recent development of the speckle-based at-wavelength metrology techniques will be presented. Representative examples of the applications of the speckle-based technique will also be given – including optimization of X-ray mirrors and characterization of compound refraction lenses. Such a high-precision metrology technique will be extremely beneficial for the manufacture and in-situ alignment/optimization of X-ray mirrors for next-generation synchrotron beamlines.

The design and evaluation of the expected performance of new optical systems requires sophisticated and reliable information about the surface topography for planned optical elements before they are fabricated. The problem is especially complex in the case of x-ray optics, particularly for the X-ray Surveyor under development and other missions. Modern x-ray source facilities are reliant upon the availability of optics with unprecedented quality (surface slope accuracy < 0.1μrad). The high angular resolution and throughput of future x-ray space observatories requires hundreds of square meters of high quality optics. The uniqueness of the optics and limited number of proficient vendors makes the fabrication extremely time consuming and expensive, mostly due to the limitations in accuracy and measurement rate of metrology used in fabrication. We discuss improvements in metrology efficiency via comprehensive statistical analysis of a compact volume of metrology data. The data is considered stochastic and a new statistical model called Invertible Time Invariant Linear Filter (InTILF) is developed now for 2D surface profiles to provide compact description of the 2D data additionally to 1D data treated so far. The model captures faint patterns in the data and serves as a quality metric and feedback to polishing processes, avoiding high resolution metrology measurements over the entire optical surface. The modeling, implemented in our Beatmark software, allows simulating metrology data for optics made by the same vendor and technology. The forecast data is vital for reliable specification for optical fabrication, to be exactly adequate for the required system performance.

Hard x-ray beams can be focused using refractive lenses, but depending on energy, a large number N of individual lenses stacked in a row is needed. Such a stack can be either composed of single lenses in cartridges, or lithographically fabricated lenses in a row. With N in the three-digit regime, the question arises which tolerances on lens alignment and shape have to be met not to disturb the focus. Here we use analytical and numerical calculations based on a Zernike polynomial expansion to give such error bounds for typical set-ups.

We employ start–to-end simulations to model coherent diffractive imaging of single biomolecules using x-ray free electron lasers. This technique is expected to yield new structural information about biologically relevant macromolecules thanks to the ability to study the isolated sample in its natural environment as opposed to crystallized or cryogenic samples. The effect of the solvent on the diffraction pattern and interpretability of the data is an open question. We present first results of calculations where the solvent is taken into account explicitly. They were performed with a molecular dynamics scheme for a sample consisting of a protein and a hydration layer of varying thickness. Through R–factor analysis of the simulated diffraction patterns from hydrated samples, we show that the scattering background from realistic hydration layers of up to 3 Å thickness presents no obstacle for the resolution of molecular structures at the sub–nm level.

We present the application of fully- and partially-coherent synchrotron radiation wavefront propagation simulation functions, implemented in the "Synchrotron Radiation Workshop" computer code, to create a ‘virtual beamline’ mimicking the Coherent Hard X-ray scattering beamline at NSLS-II. The beamline simulation includes all optical beamline components, such as the insertion device, mirror with metrology data, slits, double crystal monochromator and refractive focusing elements (compound refractive lenses and kinoform lenses). A feature of this beamline is the exploitation of X-ray beam coherence, boosted by the low-emittance NSLS-II storage-ring, for techniques such as X-ray Photon Correlation Spectroscopy or Coherent Diffraction Imaging. The key performance parameters are the degree of Xray beam coherence and photon flux, and the trade-off between them needs to guide the beamline settings for specific experimental requirements. Simulations of key performance parameters are compared to measurements obtained during beamline commissioning, and include the spectral flux of the undulator source, the degree of transverse coherence as well as focal spot sizes.

With the progress of achieving diffraction-limited X-ray focus, ptychography offers a unique and powerful tool to provide quantitative reconstruction of the complex-valued wavefront of a focused beam. Propagation of the reconstructed wavefront essentially describes complete performance characterization of the optics. We will present the accumulated efforts at NSLS-II on exploring the capability of ptychography to quantify focusing performance of a variety of hard X-ray optics, including K-B mirrors, zone plates, multilayer Laue lenses [1-3]. Presentation will also elaborate on our recent development of monolithically bonded MLLs as a signal optical component for scanning probe microscope applications [4,5]. References: [1] X. Huang, et al., “Quantitative X-ray wavefront measurements of Fresnel zone plate and K-B mirrors using phase retrieval”, Optics Express, 20, 24038-24048 (2012). [2] X. Huang, et al., “11 nm hard X-ray focus from a large-aperture multilayer Laue lens”, Scientific Reports, 3, 3562 (2013). [3] X. Huang, et al., “Achieving hard X-ray nanofocusing using a wedged multilayer Laue lens”, Optics Express, 23, 12496-12507 (2015). [4] E. Nazaretski, et al., “Development and characterization of monolithic multilayer Laue lens nanofocusing optics"”, Applied Physics Letters, 108, 261102 (2016). [5] X. Huang, et al., “Hard x-ray scanning imaging achieved with bonded multilayer Laue lenses”, submitted, (2017).

In X-ray computed tomography (CT), scattered radiation plays an important role in the accurate reconstruction of the inspected object, leading to a loss of contrast between the different materials in the reconstruction volume and cupping artifacts in the images. We present a Monte Carlo simulation tool for spectral X-ray CT to predict the scattered radiation generated by complex samples. An experimental setup is presented to isolate the energy distribution of scattered radiation. Spectral CT is a novel technique implementing photon-counting detectors able to discriminate the energy of incoming photons, enabling spectral analysis of X-ray images. This technique is useful to extract efficiently more information on energy dependent quantities (e.g. mass attenuations coefficients) and study matter interactions (e.g. X-ray scattering, photoelectric absorption, etc...). Having a good knowledge of the spectral distribution of the scattered X-rays is fundamental to establish methods attempting to correct for it. The simulations are validated by real measurements using a CdTe spectral resolving detector (Multix ME-100). We observed the effect of the scattered radiation on the image reconstruction, becoming relevant in the energy range where the Compton events are dominant (i.e. above 50keV).

This recording is for the presentation titled, “SPECTRA demonstration”, part of the 2017 SPIE symposium on Optics + Photonics

“Sirepo” is an open source cloud-based software framework which provides a convenient and user-friendly web-interface for scientific codes such as Synchrotron Radiation Workshop (SRW) running on a local machine or a remote server side. SRW is a physical optics code allowing to simulate the synchrotron radiation from various insertion devices (undulators and wigglers) and bending magnets. Another feature of SRW is a support of high-accuracy simulation of fully- and partially-coherent radiation propagation through X-ray optical beamlines, facilitated by so-called “Virtual Beamline” module. In the present work, we will discuss the most important features of Sirepo/SRW interface with emphasis on their use for commissioning of beamlines and simulation of experiments at National Synchrotron Light Source II. In particular, “Flux through Finite Aperture” and “Intensity” reports, visualizing results of the corresponding SRW calculations, are being routinely used for commissioning of undulators and X-ray optical elements. Material properties of crystals, compound refractive lenses, and some other optical elements can be dynamically obtained for the desired photon energy from the databases publicly available at Argonne National Lab and at Lawrence Berkeley Lab. In collaboration with the Center for Functional Nanomaterials (CFN) of BNL, a library of samples for coherent scattering experiments has been implemented in SRW and the corresponding Sample optical element was added to Sirepo. Electron microscope images of artificially created nanoscale samples can be uploaded to Sirepo to simulate scattering patterns created by synchrotron radiation in different experimental schemes that can be realized at beamlines.

The evolution of the hardware platforms, the modernization of the software tools, the access to the codes of a large number of young people and the popularization of the open source software for scientific applications drove us to design OASYS (ORange SYnchrotron Suite), a completely new graphical environment for modelling X-ray experiments. The implemented software architecture allows to obtain not only an intuitive and very-easy-to-use graphical interface, but also provides high flexibility and rapidity for interactive simulations, making configuration changes to quickly compare multiple beamline configurations. Its purpose is to integrate in a synergetic way the most powerful calculation engines available. OASYS integrates different simulation strategies via the implementation of adequate simulation tools for X-ray Optics (e.g. ray tracing and wave optics packages). It provides a language to make them to communicate by sending and receiving encapsulated data. Python has been chosen as main programming language, because of its universality and popularity in scientific computing. The software Orange, developed at the University of Ljubljana (SLO), is the high level workflow engine that provides the interaction with the user and communication mechanisms.

The mutual optical intensity (MOI) is a four-dimensional coherence function and contains the full coherence information of the beam. The propagation of mutual optical intensity through a soft x-ray beamline is analyzed with a new developed model named MOI. The MOI model is based on statistical optics. The wavefront is separated into many elements and every element is assumed to has full coherence and constant complex amplitude, which is reasonable if the dimension of element is much smaller than the coherent length and beam spot size. The propagation of MOI for every element can be analytically solved with Fraunhofer or Fresnel approximations. The total MOI propagation through free space can be obtained by summing the contribution of all elements. Local stationary phase approximation is implemented to simulate MOI propagating through ideal mirrors and gratings. The MOI model provides not only intensity profile, but also wavefront and coherence information of the beam. These advantages make MOI model a useful tool for beamline design and optimization. The nano-ARPES beamline at SSRF is analyzed using the MOI model. A zone plate is used to focus the beam. The intensity profile and local coherence degree at the zone plate are acquired. The horizontal coherence is much worse than the vertical one. By cutting the horizontal beam with the exit slit the horizontal coherence can be improved but at the flux loss. The quantitative analysis on the coherence improvement and flux loss at different exit slit size are obtained with the MOI model.

The PENELOPE Monte Carlo simulation code was used alongside the SpekCalc code to simulate X-ray energy spectra from a VJ Technologies’ X-ray generator at a range of anode voltages. The PENELOPE code is often utilised in medicine but is here applied to develop coded aperture and pinhole imaging systems for security purposes. The greater computational burden of PENELOPE over SpekCalc is warranted by its greater flexibility and output information. The model was designed using the PENGEOM sub-tool and consists of a tungsten anode and five layers of window materials. The photons generated by a mono-energetic electron beam are collected by a virtual detector placed after the last window layer, and this records the spatial, angular and energy distributions which are then used as the X-ray source for subsequent simulations. The process of storing X-ray outputs and using them as a virtual photon source can then be used efficiently for exploring a range of imaging conditions as the computationally expensive electron interactions in the anode need not be repeated. The modelled spectra were validated with experimentally determined spectra collected with an Amptek X-123 Cadmium Telluride detector placed in front of the source.

The PENELOPE Monte Carlo simulation code was used to determine the optimum thickness and aperture diameter of a pinhole mask for X-ray backscatter imaging in a security application. The mask material needs to be thick enough to absorb most X-rays, and the pinhole must be wide enough for sufficient field of view whilst narrow enough for sufficient image spatial resolution. The model consisted of a fixed geometry test object, various masks with and without pinholes, and a 1040 x 1340 pixels’ area detector inside a lead lined camera housing. The photon energy distribution incident upon masks was flat up to selected energy limits. This artificial source was used to avoid the optimisation being specific to any particular X-ray source technology. The pixelated detector was modelled by digitising the surface area represented by the PENELOPE phase space file and integrating the energies of the photons impacting within each pixel; a MATLAB code was written for this. The image contrast, signal to background ratio, spatial resolution, and collimation effect were calculated at the simulated detector as a function of pinhole diameter and various thicknesses of mask made of tungsten, tungsten/epoxy composite or bismuth alloy. A process of elimination was applied to identify suitable masks for a viable X-ray backscattering security application.

Synchrotron Radiation Workshop (SRW) is a powerful synchrotron radiation simulation tool and has been widely used at synchrotron facilities all over the world. During the last decade, many types of X-ray wavefront sensors have been developed and used. In this work, we present our recent effort on the development of at-wavelength metrology simulation based on SRW mainly focused on the Hartmann Wavefront Sensor (HWS). Various conditions have been studied to verify that the simulated HWS is performing as expected in terms of accuracy. This at-wavelength metrology simulation tool is then used to align KB mirrors by minimizing the wavefront aberrations. We will present our optimization process to perform an ‘in situ’ alignment using conditions as close as possible to the real experiments (KB mirrors with different levels of figure errors or different misalignment geometry).

High-accuracy physical optics calculation methods used in the “Synchrotron Radiation Workshop” (SRW) allow for multiple applications of this code in different areas, covering development, commissioning, diagnostics and operation of X-ray instruments at light source facilities. This presentation focuses on the application of the SRW code for the simulation of experiments at these facilities. The most complete and most detailed simulation of experiments with SRW is possible in the area of elastic coherent scattering, where the interaction of radiation with samples can be described with the same transmission-type “propagators” that are used for the simulation of fully- and partially-coherent radiation propagation through X-ray optical elements of beamlines. A complete “source-to-detector” simulation of such an experiment for a lithographic sample is described here together with comparisons of the simulated coherent scattering data with actual measurements results, obtained at the Coherent Hard X-ray (CHX) beamline of the National Synchrotron Light Source II (NSLS-II). Particular attention is paid to the analysis of visibility of speckles and intensity levels in the scattered radiation patterns at different degrees of coherence of the radiation entering the sample.