We discuss some latest development in home-lab based x-ray diffractometers with focuses on optics, detectors, and software.
There is no doubt that synchrotron radiation provides the best beam - high brilliance, high collimation, and continuously tunable energy - that no home-lab based sources so far can match. Many great scattering works have been done at synchrotron radiation facilities around the world in the past decade. However, this does not mean all excellent scattering experiments can only be done with synchrotron radiation. With the rapid development of new technologies, in particular the optics, detectors, and software, home-lab based diffractometers are capable of performing very sophisticated scattering experiments that were hardly possible not too long ago.
Newer x-ray diffractometers typically have a modular design, making switching among different system configurations simple and easy. For example, it takes only minutes for a user to switch from standard Bragg-Brentano optics to parallel beam optics or focusing beam optics with an easy swap of slits or optical mirrors. The newer diffractometer may also have a versatile goniometer base, allowing easy adaptation of different sample stages for various types of measurements, such as powder, thin film, in-plane, high-resolution, small-angle scattering, residual stress, pole figure, controlled environment etc. The modern diffractometers also allow users to choose what detectors are best for their applications. 0D, 1D and 2D detectors should be easily adapted to the diffractometer system. Finally, the newer diffractometers should have automatic optics and sample alignment capabilities.
Some examples will be given to demonstrate the various capabilities of the modern diffractometers with advanced new technologies.

Diffraction studies on technical materials often require hard X-rays in the range of 40-80 keV. In this energy range studies are often limited by conventional X-ray detectors since the efficient detection has to be comprised with detector limitations such as limited time resolution and noise behavior. Hybrid photon counting (HPC) detectors enable noise-free X-ray detection with high dynamic range and excellent stability at high frame rates, properties which are essential for superior data quality. Until now this technology mainly used Silicon as sensor material offering excellent detection efficiency from about 3 to 25 keV. For harder X-ray energies CdTe sensors allow to increase the efficiency tremendously, which can lead to new cutting edge experiments in material science.
A large-area CdTe HPC detector suitable for high-energy synchrotron applications at X-ray energies from about 8 keV to 80 keV has been developed. The detector has 300k pixels with a sensitive area of 83 mm x 106 mm and a pixel size of 172 mu;m x 172 mu;m. It was built in hybrid-pixel technology by bumpbonding PILATUS3 CMOS readout ASICs [1] to six large pixelated CdTe sensors with a size of 42 mm x 34 mm and a thickness of 1000 mu;m. The PILATUS3 ASIC with instant retrigger technology (count-rate capability of up to 10⁷ photons per second per pixel) is operated in its modes specifically implemented for compatibility with CdTe, which are 'negative bias polarity' for electron collection and 'reduced shaper gain' for processing the high-energy X-ray pulses. The detector has been thoroughly characterized in terms of energy resolution, long-term stability of CdTe material, quantum efficiency, point-spread function and count rate using an X-ray tube setup and at a synchrotron (BESSY). These characterization results together with first X-ray experiments at the synchrotron confirm the suitability of this large area CdTe detector for high-energy synchrotron applications such as X-ray diffraction tomography [2]. We will present first studies on test objects demonstrating the advantages of this technology in material science.
The properties of HPC detectors are also ideal for diffractive and phase-contrast imaging. The newly developed EIGER HPC detector [3] features a high frame rate of 3 kHz and a pixel size of only 75 mu;m x 75 mu;m. Tomographic applications from synchrotron-based small-angle x-ray scattering (SAXS) imaging [4] and coherent diffractive ptychographic imaging [5] profit from the new improvements. The first experiments with this technology will be presented.
[1] T. Loeliger et al., IEEE Nucl Sci Symp Conf Rec, pp. 610-615 (2012)
[2] S. D. M. Jacques et al., Angew. Chem. Int. Ed. 50, 10148 (2011)
[3] R. Dinapoli et al., Nucl. Instrum. Meth. Phys. Res. A 650, 79 (2011)
[4] O. Bunk et al., New J. Phys. 11, 123016 (2009)
[5] M. Guizar-Sicairos et al., Opt. Express 22, 14859 (2014)

It is often a difficult task to make a precise link between measurements of the electronic or geometric structure and a well-defined point in the phase diagram of the system under study. A number of experiments rely on the assumption that, during the measurements the expected thermodynamic conditions are met by choosing the temperature and pressure given by the phase diagram. The more complex the phase diagram of a system is, the more often this assumption is not correct. The best way to overcome those drawbacks is to perform so called in situ experiments, where the sample is brought to the state of interest while acquiring thermodynamic and structural information. The coupling of differential scanning calorimetry (DSC) with synchrotron based techniques like diffraction and spectroscopy could be a way to overcome the above described problems. The experimentalist is not just fixing a temperature; he is getting the response of the sample to an external stimulus which allows the determination of its exact thermodynamic state when measuring its structural and electronic properties.
This contribution is focused on the integration of calorimetry into an XAS beamline. The advantage of combining these techniques is that on one side calorimetry gives access to the energetics associated to the phase transitions and on the other side, XAS is a spectroscopic tool sensitive to the local order of a given specimen in the ordered as well in the disordered state. The benefit of such a coupled set-up [1] will be illustrated through various examples dealing phase transitions in glass forming materials.
The first example is concerned with the crystallization of Ge₁₅Te₈₅ that was among the first systems investigated for switching effects [2]. Here we will focus on the atomic and vibrational change occurring during the glass transition. The second and third examples will deal with Antimony-based amorphous alloys (Ge₁₅Sb₈₅ and Ga_xSb_1-x) that are potential candidates for phase change memories but present a tendency towards phase separation [3,4]. Owing to enthalpy calculations combined to an EXAFS analysis of the local order around each element, the composition of the crystallizing phases as well as the structural mechanisms leading to phase separation will be discussed.
References
[1] P. Zalden, et al. J. Synchrotron Rad.19(5) 806 (2012).
[2] S. R. Ovshinsky, Phys. Rev. Let.,21(20) p 1450 (1968).
[3] M. Putero et al., APL Mater. 1, 062101 (2013).
[4] P. Zalden et al. J. Appl. Phys. 107, 104312 (2010).

Latest innovation in high brightness X-ray sources for microdiffraction, more efficient X-ray detectors combined to the intrinsic capability of X-rays to probe materials at sub nanometer scale are opening new opportunities for X-ray metrology for the characterization of new materials and structures like FINFETs at the advanced technology nodes. The term FINFET in the technical literature is used somewhat generically to describe any fin-based, multi-gate transistor architecture
Optical Scatterometry, also referred to as OCD is presently the metrology of choice for shape metrology and critical dimensions in semiconductor. However for the next generation technology nodes (less than 10nm), optical scatterometry will start to reach its physical limit.
In this talk, I will present recent development of X-ray diffraction with high brightness laboratory X-ray source for applications of 2D and 3D semiconductor structures. In particular, I will report a detailed strain analysis of the 3 dimensional FINFET structures . Other parameters of relevance are compositional gradients and dimensional parameters like pitch, pitch walking and shape. I will also discuss the status of the art of the laboratory X-ray instrumentation and the need of high brightness X-ray sources for microelectronics applications.

The nano-to-mesoscale structure of carbon-based materials is of interest in diverse fields such as organic electronics for energy applications, biomimetic materials, and even biological tissues. However, measurement of such structure is particularly difficult due to the materials&’ radiation sensitivity, low contrast with traditional probes, and low degree of crystallinity. Recent developments in resonant (or ‘anomalous&’) X-ray techniques utilizing unique electronic transitions in the molecules have demonstrated exquisite sensitivity to ordering in these materials. Due to the complex interactions involved in these measurements, however, results have been limited to qualitative interpretations. Here we demonstrate the extraction of quantitative information on the nano-to-mesoscale structure of organic thin films utilizing spectral analysis of resonant, polarized x-ray scattering experiments across an absorption edge. We demonstrate reciprocal space mapping techniques that minimize exposure, a proper yet simple scattering model beyond the Born Approximation, and analysis methods to separate multiple sources of scattering to achieve robust, quantitative measurement of molecular composition and conformation within domains and nanostructures.

High nitrogen martensitic stainless steels with different tempering condition were studied by Transmission Electron Microscope(TEM), SAXS and SANS.
SAXS and SANS profiles were obtained by in-house laboratory system. SANS measurements have also performed using research reactor, HANARO in KAERI and compere to the in-house SANS profiles. All profiles with tempering higher than 450C shows formation of nano-size heterostructure with diameter of 1nm.
Careful TEM observation reveal that the heterostructure has a feature of omega phase with hexagonal structure. Composition of omega phase is discussed with the combined method of SAXS and SANS.

With the advent of high brilliance X-ray sources such as the so-called Third Generation Synchrotron Radiation Sources, the X-Ray Free Electron Laser Sources and the planned Diffraction Limited Storage Rings, experiments using coherent X-ray beams to study the structure and dynamics of materials are becoming increasingly popular. In this talk we will briefly review the use of X-ray Photon Correlation Spectroscopy at Grazing Incidence to study the dynamics of surfaces and interfaces. Applications have ranged from the study of liquid and polymeric surface fluctuations, to dynamics of buried inhomogeneous nanostructures, domains in magnetic films, reconfigurations at metal surfaces and non-equilibrium phenomena. We will also discuss possible future developments in this area of research.
This work has been supported by Grants Nos. DE-SC0003678 and DE-FG02-04ER46173 from Basic Energy Sciences, U.S. Department of Energy.

X-ray photon correlation spectroscopy is a well established scattering technique for studying dynamics in a wide variety of systems. It is analogue to dynamic light scattering but due to high penetrating power and short wavelength of the X-rays, it allows the investigation of opaque samples and the access to atomic length scale. Microscopic dynamics at the atomic level is of great interest in particular for glass community. However its exploration with XPCS has not been possible until recently, due to the low scattering signal. Increase in coherent flux and advance in the data treatment of sparse signal [1,2] opened unique capabilities of probing slow diffusion in crystals [3] and atomic relaxations in glasses [4-7].
Here we present the experimental details of XPCS measurements applied to glasses. In particular we show the data analysis protocol that enables to extract the intensity autocorrelation function from single photon events.
Using a new event correlation scheme we have investigated for the first time the temperature dependence of the structural relaxation process in a metallic glass-former at inter-atomic distances [4,5]. We found a dynamical crossover between the supercooled liquid and glassy states at the calorimetric glass transition temperature. This crossover is characterized by a change in the shape of the correlation functions, β, from stretched (lower than 1) in supercooled liquid to compressed (larger than 1) in the glass. The dynamics in the glass is furthermore accompanied by the presence of a complex aging behavior which seems universal in rapidly quenched metallic glasses [6].
Another system studied was a sodium silicate glass 80%SiO2-20%Na2O [7]. It is a prototypical network glass. The static structure factor of the sodium silicate glass shows a prepeak at wave vector Q~0.9 #8491;^-1 related to the sodium diffusion channels and a broad first diffraction peak coming from the silicon-oxygen network. For the first time we measured the wave vector dependence of the relaxation time at various temperatures. Our results reveal a fast atomic motion that depends on the thermal protocol used. Moreover the relaxation time of the glass is modulated by the static structure factor in analogy to the "de Gennes" narrowing observed in liquids.
[1] M. Leitner PhD thesis, University of Vienna, Austria. (2010).
[2] Y. Chushkin et al. J. Appl. Cryst. 45, 807-813 (2012).
[3] M. Leitner et al. Nat. Mater. 8, 717-720 (2009).
[4] B. Ruta et al. Phys. Rev. Lett. 109, 165701 (2012).
[5] B. Ruta et al. AIP Conf. Proc. 1518, 181 (2013).
[6] B. Ruta et al. J. Chem. Phys. 138, 054508 (2013).
[7] B. Ruta et al. Nat. Commun. 5, 3939 (2014).

The analysis of three-dimensional microstructures by X-ray diffraction contrast tomography (DCT) and grain growth simulations gives new insights into grain growth and grain boundary properties at sintering temperatures in ceramics. DCT has been successfully applied to the analysis of 3D grain structures in strontium titanate. The technique is now employed to follow grain growth during successive annealing steps at sintering temperature. The evolution of the 3D grain boundary network is obtained in a multiple time step series with all crystallographic information of the neighbouring grains. Shape evolution is followed quantitatively using moment invariants.This shows faceting of certain grain boundaries. Faceting occurs on grain boundaries with a {100} orientation of one grain. Some large grains predominantly evolve {100} faces and take a near “cubic” shape.

Despite decades of research on electrochemical cells, surprisingly little is known about the molecular-level processes occurring near electrodes in contact with electrolytes under operating conditions. The atomic and electronic structures of the electrode surface determine the chemical activity but frequently differ from those of a simply terminated bulk crystal. Here, we synthesize operando electrochemical and X-ray studies of the photocatalytic activity of a model system, the (001) surface of SrTiO₃ towards the water splitting reaction under active potential control, with novel ab initio joint density-functional theory (JDFT) calculations. Pre-treating the electrode surface, by biasing to potentials where oxygen evolution occurs in basic medium, irreversibly reorders the surface and nearly triples the photo-induced water splitting activity at open circuit. Our JDFT interpretation of the X-ray data suggests that the electrochemical pre-treatment reorganizes the surface of the SrTiO₃ electrode into a biaxially strained, anatase-like structure. This work illustrates how the combination of in situ techniques with theory, opens a promising path towards better understanding of surface reactivity in electrolytic media and the design of improved catalysts.

X-ray Photon Correlation Spectroscopy (XPCS) offers unprecedented sensitivity to the dynamics of structural changes in materials. However, XPCS facilities have generally been limited to microstructure length scales smaller than asymp; 50 nm, thus eliminating large classes of materials that are of major technological importance. In recent years, we have been able to extend the range of this technique dramatically (into the micrometer scale regime) by combining XPCS speckle measurements with Bonse-Hart ultrasmall-angle scattering (USAXS) studies at the Advanced Photon Source. [1-4] While USAXS characterizes microstructures over the nanometer-to-micrometer scale range, use of a small entrance slit allows the coherence of the undulator X-ray beam to be exploited to give XPCS measurements of the internal microstructure dynamics. At the large end of the scale range, the slower material dynamics are well matched to the time resolution offered by USAXS-based XPCS. Using a point-counting configuration at selected Q values, we have established that phenomena previously observed for nanoparticle dispersions, including de Gennes narrowing, extend to these coarser length scales. [4] This is important because the slower relaxation times at mesoscale lengths in aqueous colloidal suspensions can be followed directly using USAXS-XPCS. Thus, phenomena such as bimodal interparticle interactions or suspension liquid phase transformations can be studied at the mesoscale while retaining relevance for nanoscale phenomena, where much shorter relaxation times make direct studies difficult.
USAXS-XPCS can also be configured to make repeated, short USAXS scans to detect incipient (precursor) microstructure changes under non-equilibrium conditions by following associated changes in the observed speckles. [3] We have applied this approach to study amorphous-to-crystalline phase transformations in dental composites. [3]
Finally, we have explored the feasibility of conducting simultaneous multiple USAXS-XPCS measurements using a nanofabricated slit array with each partially coherent X-ray beam paired to a group of pixels on a position-sensitive detector. This would allow rapid measurement of the dynamics in a heterogeneous material or could be used to follow a reaction front advancing across the sample.
[1] F. Zhang, A.J. Allen, L.E. Levine, J. Ilavsky, G.G. Long A.R. Sandy; J. Appl. Cryst., 44, 200-212 (2011).
[2] F. Zhang, A.J. Allen, L.E. Levine, J. Ilavsky, G.G. Long; Metall. Mater. Trans. A, 43, 1445-1453 (2012).
[3] F. Zhang, A.J. Allen, L.E. Levine, L. Espinal, J.M. Antonucci, D. Skrtic, J.N.R. O&’Donnell, J. Ilavsky; J. Biomed. Mater. Res. A, 100, 1293-1306 (2012).
[4] F. Zhang, A.J. Allen, L.E. Levine, J. Ilavsky, G.G. Long; Langmuir29, 1379-1387 (2013).

Time-resolved x-ray diffraction can provide important insights into the evolution of the structure of a material during dynamic loading, such as the elastic strains in individual phases, crystallographic texture, and the development of new (possibly metastable) phases. We performed time-resolved x-ray diffraction on bulk polycrystalline metals and alloys undergoing dynamic compressive loading in a split Hopkinson (Kolsky) bar apparatus at strain rates of approximately 2500 s^minus;1 with exposures as short as 70 ns. The diffraction patterns were recorded in transmission onto the Cornell Keck-PAD, a high-speed analog pixel array detector, using 10 keV x-rays from the Cornell High Energy Synchrotron Source (CHESS). Varying the orientation of the Kolsky bar with respect to the incident x-rays and the position of the detector allowed us vary the orientation of the scattering vector with respect to the loading direction. As an example we discuss texture evolution of magnesium alloy AZ31 under dynamic compression. We observed a decrease in scattering from the (0002) planes and a corresponding increase in scattering from the (10-10) planes with the scattering vector perpendicular to the loading axis, while the opposite behavior was observed with the scattering vector approximately parallel to the loading axis. This is consistent with texture evolution in the form of a reorientation of the magnesium lattice due to activation of {10-11}<10-1-2> compression twins in response to dynamic deformation. Finally, we will discuss prospects for future developments in experiments of this kind, taking advantage of new detectors and x-ray sources.

Through undulator sources at 3^rd generation synchrotrons, highly coherent X-rays with sufficient flux are nowadays routinely available, which allow carrying over photon correlation spectroscopy (PCS) from visible light to the X-ray regime. X-ray photon correlation spectroscopy (XPCS) is based on the auto-correlation of X-ray speckle patterns during the temporal evolution of a material and provides access both to equilibrium and non-equilibrium properties of materials at the Angstrom scale. Owing to current technical limitations (detector readout), XPCS is typically used for the detection of slow dynamics on the scale of seconds. The variety of scattering geometries employed in conventional X-ray analysis can be combined with XPCS, as done in this work, where bulk diffraction (XRD) and surface-sensitive scattering (GISAXS) were used to study shape memory alloys undergoing a structural, diffusionless (martensitic) transformation.
The vast majority of martensitic transformations (MT) is viewed as being athermal, although time-dependent phenomena such as incubation time or ageing effects have been known for a long time. XPCS is able to reveal non-equilibrium dynamics using two-time correlation functions [1]. This technique has only recently been applied to MT [2,3]. In particular, it can reveal - on a purely experimental basis - non-ergodic processes in the vicinity of the MT, elucidating the actual transformation path. Microstructural avalanches that accompany MT can be observed and quantified [2] as well as ageing processes [3].
Our experiments on Au_50.5Cd_49.5 and Ni₆₃Al₃₇ single crystals indicate the following:
a) Bulk — Non-equilibrium features can be observed for both alloys in the direct vicinity of the MT, which are partially superimposed with signatures of microstructural avalanches. The revealed slow dynamics can be quantified in terms of stretched exponential functions and is consistent with the “symmetry conforming short-range-order” model based on short-range diffusion [4].
b) Surface — Grazing incidence small angle X-ray scattering (GISAXS) was employed to study the temperature-dependent evolution of surface roughness from the precursor regime (several 10 K above the MT) to the fully developed martensitic surface relief. The measurements indicate pronounced non-equilibrium dynamics in the precursor regime and a peculiar type of precursor not observed in the bulk (non-monotonous correlation function). We conclude that significant premonitory surface fluctuations must be present in the austenitic state. This precursor effect is more pronounced in Ni-Al than in Au-Cd.
[1] A. Malik et al., Phys. Rev. Lett. 81, 5832 (1998).
[2] C. Sanborn et al., Phys. Rev. Lett. 107, 015702 (2011).
[3] L. Müller et al., Phys. Rev. Lett. 107, 105701 (2011).
[4] X. Ren et al., Phys. Rev. Lett. 85, 5 (2000).

Four Dimensional (4D) X-ray Microscopy with a submicron beam size was used to follow the evolution of strains in off-stoichiometric NiMnGa twinned crystals near a type I (hard) twin boundaries under a magnetic field. A laminate A/B microstructure was revealed near the twin boundaries in the “A” variant. Large strain gradients were observed in the “C” variant in the immediate vicinity of the type I twin boundary: the lattice is under large tensile strains ~0.4% along the c- axes within the first micron. Distinct “a” and “b” lattice parameter evolution with temperature and magnetic field was demonstrated. In an applied magnetic field, the strain field was observed at larger distances from the twin boundary and became more complex. Stochastic twin boundary motion was observed after the magnetic field reaches a certain critical value. Research sponsored by the LDRD Program of Oak Ridge National Laboratory, U. S. Department of Energy.

Image-based characterization data have enabled many important discoveries related to polycrystalline microstructure. New high energy x-ray methods - coupled with detailed structure-based simulations - effectively build on these discoveries by providing real time material response information. The Insitmu; center at the Cornell High Energy Synchrotron Source (CHESS) was created to enable researchers to understand the response of polycrystalline structural materials subjected to load. New loading and positioning capabilities enable the creation of grain maps and real-time measurement of lattice strains within each deforming crystal. FEpX, a parallel finite element code developed over the past 20 years at Cornell, is installed on the CHESS compute farm. Users with CHESS projects have access to both experimental and computational resources.

Ferromagnetic shape memory alloys have shown tremendous potential as active components for next-generation actuators and smart devices due to their unusually large magnetic-field-induced strains and fast response times. Unlike in conventional shape memory alloys, in which a martensitic phase transformation occurs, in FSMA the shape memory effect is driven by twin boundary motion of the martensitic phase, leading to reorientation of the crystallographic twin variants. By using time-resolved high-energy synchrotron diffraction, we have resolved [1] the kinetics of twin boundary motion in a ferromagnetic shape memory alloy of Ni-Mn-Ga. We show that the temporal evolution of twin reorientation during the application of a magnetic field is described by thermally-activated creep motion of twin boundaries over a distribution of energy barriers. The dynamical creep exponent mu; was found to be ~ 0.5, suggesting that the distribution of energy barriers is a result of short-range disorders.
[1] A. Pramanick et al., Phys. Rev. Lett., 112, 217205 (2014).
This research was supported in part by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL), managed by UT-Battelle, LLC for the U. S. Department of Energy under Contract No. DE-AC05-00OR22725. XLW acknowledges the support by a grant from the Research Grants Council of Hong Kong Special Administrative Region (Project No. CityU 122713). Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. Technical assistance from Richard Spence during experiments at APS is gratefully acknowledged. A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.

High-resolution hard x-ray spectroscopies (XES, HERFD, RIXS, XRS) are now well-established characterization tools for providing insights of material&’s electronic and geometric structure. The high brilliance synchrotron radiation beamlines have made feasible the routine study of the electronic structure and ligand environment of metal coordination compounds and active centers in metalloproteins, electrochemical process under in-situ conditions, as well as studies on catalytic systems under ambient conditions.
At SLAC National Accelerator Laboratory we have developed recently a set of high-resolution x-ray spectroscopic capabilities based on various multicrystal spectrometers. At SSRL we have built three multicrystal Johann spectrometers enabling XES/RIXS/HERDF techniques as well as X-ray Raman Spectroscopy. Representative examples of in-situ application in batteries, electrocatalysis, hydrogen storage, etc. will be shown and discussed from the ongoing spectroscopy programs of SSRL.

The texture of a worked piece of material is a result of the history of the manufacturing process. Texture control is an important tool in order to obtain the manufactured product with the desired property, such as strength, conductivity or hardness. The materials researcher is therefore not only interested in the study the final texture of a sample, but also in following the texture evolution during the formation or deformation processes. Knowledge of the evolution of preferred orientations can provide valuable information in order to optimize the manufacturing process.
In texture evolution studies, samples are often prepared and then mounted onto an X-ray diffraction system in order to measure the pole figures for a quantitative analysis. In the present study we have integrated a uniaxial tensile stage onto a Eulerian cradle in a laboratory X-ray diffraction system. Measurements can be performed while the sample experiences a certain mechanical loading. The setup allows for complete pole figure measurements with full phi-circles and chi-tilts up to 75 degrees. Changes in pole figures can be compared with the stress-strain curve recorded.
As an example, investigations have been performed on metallic samples. Thin strips of rolled copper (0.02 mm) were analyzed with increasing stresses up to 4 N.
The pole figures were of good quality such that the orientation distribution function could be determined. Changes in the ODF and fibers as a function of strain were observed. This information can be used for comparison with measurements of other mechanical and physical materials properties.

Small-angle neutron scattering (SANS) should be one of the powerful techniques to characterize nanoscopic structures in alloys; it can measure precipitates or concentration fluctuation down to sub-nanometer size; obtain number density or scattering length density of such ones quantitively while averaging over a bulk sample. It should be frequently used for new material development, however, in reality, it is not so much used. It is due to less than appropriate number of neutron facilities available and it is not so convenient to use one of such facilities in a timely manner when it is required.
One solution to this situation is to use a compact accelerator driven neutron source (CANS) with a power of 1 kW to a few tens of kW, either an electron or proton accelerator. We demonstrated that a properly designed small and median-angle neutron scattering instrument (iANS) installed at one of such facility is more than enough for such purposes.
We conducted comparison experiments with iANS at HUNS and with the 18 m SANS instrument at the HANARO 30 MW reactor in Republic of Korea. The scattering profiles obtained in high-nitrogen steel provided by Daido Steel overlaps nicely for the both data, although the Q-range covered is different; larger Q-range, 0.2 nm^-1 to 50 nm^-1, for iANS and 0.03 nm^-1 to 1.5 nm^-1 for 18 m SANS. Measuring time was 6 hrs for HUNS and 1.5 hrs for HANARO.
By optimizing SANS to a nanoscopic scale region, we can relax the incident neutron beam divergence and hence, we can gain in neutron intensity by something like 1,000 times, because measured intensity is proportional to the fourth power of angular resolution.
We demonstrated that even with the iANS at CANS at Hokkaido University (HUNS) is enough for such characterization measurements. The CANS at Hokkaido University is, 45-MeV electron linac which delivers 1 kW of beam power to a tungsten and lead composite target at Hokkaido university, coupled with a solid methane cold source running at 50 Hz. A part of the success of this of instrument is due to time-of-flight (TOF) method used for this system; the gain in intensity is one to two orders of magnitude, depending on the momentum transfer (Q) range.
We are also developing a mini-focusing type TOF SANS instrument (mfSANS), which employs an ellipsoidal neutron focusing mirror of 0.9 m length and 20 mm width, and the length of major axis of 1.25 m. We are developing a focusing mirror based on metal substrate. With mfSANS, we will be able to access minimum Q of about 2×10^-2 nm^-1, provided the scattering intensity is very strong.
We have a plan to upgrade our electron accelerator to have a few kW of electron beam power and higher performance neutron target station. It will give us about a factor of 6 intensity at sample position, which means we can measure 1 sample/1 h, which maybe enough for material development characterization.

The International Year of Crystallography (IYCr2014) aimed to improve and continue public awareness of the field, boost access to instrumentation and high-level research, nurture locally-trained crystallographers in developing nations, and increase international collaboration for the benefit of future generations.
Major projects to achieve these broad aims included:
IUCr-UNESCO OpenLabs. These are a network of crystallographic laboratories based mainly in Asia, Africa and South America, and implemented in partnership with industry. The OpenLabs facilitate hands-on training for students in modern research techniques.
IUCr- UNESCO Summit meetings. The Summit meetings brought together scientists from widely separated parts of the world, they were held in Karachi (Pakistan), Campinas (Brazil) and Bloemfontein (South Africa). The meetings, were attended by academics, industry and science administrators and focused on high-level science but also highlighted the difficulties of conducting competitive research in the developing world.
Crystal growing competitions. A major objective of IYCr2014 was also to establish an awareness of crystals and their structure in school children. A vibrant worldwide network of schools participating in crystal-growing experiments was initiated. The continued aim is to introduce students to the exciting, challenging and sometimes frustrating world of growing crystals. Winners are those who most successfully convey their experiences to the panel of judges through videos or essays.
Even though the year is coming to an end the above activities and more will continue, you can still participate in many ways and we urge you to visit www.iycr2014.org for more information and resources to assist in communicating the importance of crystallography to a wider audience.

In contrast to electron microscopists who apply both diffraction and imaging modes to study materials during the same experiment, X-ray users tend to apply either diffraction or imaging techniques. This is in part because instruments tend to operate in one mode or the other. However instruments capable of both imaging and diffraction are beginning to emerge. This talk will explore how diffraction and imaging can provide complementary information about a region of interest. Diffraction can provide information on the key phases, grain orientations, phase transformations, elastic strains in the materials while imaging can provide information on phase morphologies, cracks, microvoids, delaminations, porosity etc. Furthermore this information can be tracked over time during material processing, in service or even during healing and regeneration. Much of the talk will be focused on the study of fracture mechanics in conventional engineering materials as well as hierarchical composites and natural materials. In addition results arising from emerging techniques such as diffraction contrast tomography which exploit imaging to visualise the structural elements and diffraction to image grain boundaries and grain orientations can do much to understand materials phenomena such as grain growth and recrystallization as well as intergranular stress corrosion. Finally further opportunities for connecting the diffraction and imaging modes of synchrotron X-ray microscopy to electron microscopy within a correlative tomography framework are also explored.

Solid oxide fuel cells (SOFCs) are a very promising technology for environment-friendly renewable energy sources. There are few bottlenecks which hamper SOFCs of being widely used. One of them is the efficiency of the oxygen reduction reaction (ORR) at the cathode side of SOFC. In that sense there is a need for cheap yet effective solutions for cathode materials, and perovskite type oxides (ABO_3-δ) are promising candidates for the purpose. At present it is not clear whether ORR at the triple phase boundary or at the entire surface plays the dominant role. To get a complete picture of electro-chemical processes taking place at the cathode side an insight into the interface atomic structure is needed. Therefore we focused our studies on electrode/electrolyte interface structure determination of model SOFCs related systems by employing surface x-ray diffraction (SXRD) technique. The SXRD experiments were carried out at the European Synchrotron Radiation Facility ESRF, beamline ID03. To be close to a real application, yet to be able to interpret results, we have decided to deposit La_1-xSr_xCoO_3-δ (LSC) microelectrodes on single crystalline YSZ and perform experiments in situ with mu;m spatial resolution. For this purpose a dedicated vacuum mobile chamber for synchrotron based electro-chemistry experiments was developed in our group. With this setup we are able to create and maintain desired sample environment (e.g. oxygen pressure, sample temperature, applied potential value) as well as to check electrodes workability by impedance spectroscopy during x-ray measurements at the synchrotron. To enhance the scattering contrast between Y and Zr we resorted to anomalous XRD by measuring at respective K-edges of these elements. To be surface sensitive we measured sets of crystal truncation rods (CTRs) under different conditions and at different sample areas (underneath the electrodes and on the bare YSZ surface). We observe noticeable changes in CTRs signal intensity while varying experimental parameters. The analysis of the data has revealed that under operational conditions yttrium concentration increases in the top most YSZ atomic layer under the electrode which leads to a higher amount of oxygen vacancies and thus induces oxygen ion transport to the bulk of YSZ. In our work we show that SXRD can be employed as a tool to resolve SOFC model electrode/electrolyte interface composition changes on the atomic scale under operational conditions. We believe that these experimental results pave the way for a more complete atomic scale understanding of the surface chemistry at oxide-oxide interfaces relevant for SOFCs.

Carbon allotropes continue to be a fascinating and fertile ground for materials research. Cycloparaphenylenes (CPPs) are the shortest possible segment of armchair nanotubes, and are composed of an integer number [n] of benzene rings arranged in a "hoop". Primary interest in this molecule stems from its possible use as a building block for bottom-up nanotube synthesis. Non-[n]-selective synthesis of CPPs was first achieved in 2008, and subsequent techniques allowed for the [n]-selective production in small quantities.
Early ultraviolet and visible spectroscopy studies of CPP in solution revealed blue-shifted emission that increased with larger ring ([n]) size. This defies the typical trend for organic molecules, in which the exact opposite behavior is expected. This quality alone has prompted many theoretical attempts to fully explain the optoelectronic properties of the [n]-CPPs. In spite of a number of density functional theory (DFT) calculations having been conducted, no direct electronic structure data has been collected for these materials. In 2012 the Jasti group at BU pioneered a technique for producing crystalline [8]- and [10]-CPP at the gram-scale. Such macroscopic quantities are sufficient to perform soft x-ray analysis for detailed electronic structure information.
Synchrotron radiation provides enough flux and monochromatic selectivity to study a number of unique electronic properties, and the X1B endstation at the NSLS hosts a number of experimental tools for exactly such analysis. We present a complement of results from various techniques, including x-ray absorption, emission, and photoemission spectroscopies. Photoemission spectroscopy provides quantitative band structure and chemical environment information. The combination of absorption and emission spectroscopies effectively maps the partial density of unoccupied and occupied states. We compare all of this data with the relevant predictions from DFT calculations, and provide contrast for further theoretical modeling.
Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DEAC02-98CH10886.

Most of the microstructural information of metals at high temperature is still being obtained by the processing-quench-analysis method. The method is not only tedious and slow, but information may be lost during the quench process, as temperature-driven stresses influence the microstructure or even initiate phase transformations. Neutron diffraction, in contrast, can deliver in-situ information in real time from a large bulk average. Using the Takumi diffractometer at J-PARC and Wombat at ANSTO, we have investigated various metals while ramping the temperature up and down. The metals examined include copper, titanium and zirconium, magnesium and aluminium alloys. The evolution of lattice parameters allows the measurement of anisotropies and anomalies in thermal expansion and chemical segregation in each of the constituting or transforming phases; sudden changes in peak width showing recrystallization. Emphasis is given to the change of Bragg peak intensities due to primary extinction, which can be followed in time, relating to the defect kinetics upon crystallite recovery at annealing temperature, as well as distortions stemming from a nucleating phase. This extinction model of defect kinetics was additionally verified by the introduction of dislocations through in-situ plastic deformation during the experiment. Selected results will be discussed in the presentation.

There have been substantial advances in modeling and simulation of microstructure in 3D. These have been accompanied by equally significant advances in characterization techniques, with serial sectioning, synthetic microstructure generation and synchrotron radiation all contributing strongly. Image-based methods for solving elastic, viscoplastic and elasto-viscoplastic problems are now available to complement finite element methods. The image-based methods sidestep the difficulty of generating meshes that conform to 3D microstructures while preserving mesh quality. The FFT-based simulations originated by Pierre Suquet and Ricardo Lebensohn provide an example. The resolution available permits many aspects of heterogeneity in deformation to be investigated. Materials can also be orientation mapped non-destructively in 3D thanks to penetrating radiation at synchrotrons, which permits microstructural evolution to be characterized. High Energy X-ray Diffraction Microscopy (HEDM) is a prime example of this approach. Synthetic microstructure generation with tools such as Dream.3D now includes distributions of orientation, grain boundary character and grain morphology, even fitting the tails of distributions. Examples are given of 3D studies of twin creation during grain growth as it affects grain boundary engineering (GBE), experiment-simulation comparisons of mechanical twinning in Zr, orientation change and gradients in tensile tests of copper, fatigue crack initiation in superalloys, spatially varying strain and orientation gradients in steel, and tin whisker formation.

Atomic layer epitaxy (ALE) is a relatively new method to grow crystalline materials in a layer-by-layer fashion by separating the growth reaction into two surface-mediated, self-limiting half reactions. Recently, plasma assisted ALE (PA-ALE) has been used to grow epitaxial III-nitride films at temperatures from 180-500°C [1-2]. At these growth temperatures, the ad-atom mobility is low and the growth process is highly dependent on the quality of the growth surface. Thus, understanding the mechanism of nucleation and growth kinetics is very important to improving material quality. Since the ALE growth pressure is on the order of 1-500 mTorr, ultra-high vacuum in situ monitoring methods cannot be used to monitor the nucleation and growth mechanisms. A promising alternative method for in situ monitoring involves the use of high intensity coherent x-rays, such as from a synchrotron light source, and includes small angle reflectance/scattering, diffraction, and fluorescence.
We present initial in situ studies of the PA-ALE process using synchrotron x-ray radiation, and grazing incidence small angle x-ray scattering (GISAXS) , x-ray reflectivity (XRR), and in-plane x-ray diffraction (XRD) measurements. Investigations focus on the in situ surface preparation process, an emulated gallium flash-off, and initial stages of epitaxial growth of AlN and InN on GaN template layers grown by metalorganic chemical vapor deposition. Experiments were conducted in a custom PA-ALE growth facility installed at beamline X21 of the National Synchrotron Light Source at Brookhaven National Laboratory. Surface evolution during the in situ surface preparation process was monitored by GISAXS and the nucleation and growth processes for AlN and InN were monitored using GISAXS, XRR, and in-plane XRD. Atomic force microscopy (AFM), x-ray photoelectron spectroscopy and out-of-plane XRD were employed as post growth characterizations.
In situ XRR measurements of an optimized growth process for AlN on a 450°C substrate revealed a 0.08 nm/cycle growth rate. An in situ GISAXS measurement at optimal growth conditions clearly shows each half-cycle of the AlN growth process. Ex situ AFM measurements confirm that the surface roughness after growth was similar (RMS roughness =0.74 nm) to that of the GaN substrate. We compare the in situ in-plane synchrotron XRD study with previous reports [2] of AlN/GaN grown in a Cambridge Nanotech Fiji reactor to assess the material quality grown in the in situ chamber. The in-plane XRD measurement on pre-grown ALE AlN confirms the epitaxial nature and wurtzite structure with 60 degree symmetry in phi;-scan. These early results demonstrate that in situ synchrotron x-ray characterization methods are a powerful tool for exploring the epitaxial nucleation and growth mechanisms of III-nitride layers by PA-ALE.
1. N. Nepal, et al., J. Cryst. Growth and Des. 13, 1485 (2013).
2. N. Nepal, et al., Appl. Phys. Lett. 103, 082110 (2013).

Boron carbide (B₄C) is an important ultrahigh melting temperature covalent solid which is considered the foremost material of choice for armor applications. Besides its high hardness and strength, B₄C is a small polaron conductor. Here, we report on the results of an in situ time- resolved EDXRD study as a function of electric field and temperature whereby the densification phenomena of a 50 nm median size nano-B₄C particulate system has analyzed at the unit cell level over times scales that are commensurate with diffusion time scales by using polychromatic x-rays with photon energies up to 200 keV. Non-isothermal conditions runs under 45V/cm electric field and 35^oC/min heating rate led us to the discovery of maximum current draw of 10 A at 711 ^oC, corresponding to an instantaneous power absorption density of 398 Watt/cm³. The maximum current draw is accompanied by an anomalous volume expansion of the unit cell by 1.308% which is also anelastic which relaxes, again, anelastically as the electric field is reduced. The observed anelastic volume expansion and contraction is accompanied with an increase in density from 67% to 95% in 324 seconds at 711 ^oC in the form of a burst which we call Burst Mode Densification. No appreciable grain growth or phase transformation was observed in ex situ SEM analyses. The ultralow process densification temperatures and time clearly indicate that mass transport in this nanoparticulate system under the action of both thermal and electrical fields are of an electrochemical origin in which particle-particle contacts and associated tunneling phenomena should play a role. The implementation of ultrahigh energy EDXRD method described here is the first of its kind in monitoring the evolution of nanoparticulate matter at the unit cell scale enabling one to analyze transient behavior that is otherwise not possible with conventional Bragg-Brentano methods.

The European Spallation Source (ESS) is a multi-disciplinary research centre based on the world&’s most powerful neutron source [1]. This new facility will be around 30 times brighter than today's leading facilities, enabling new opportunities for researchers in the fields of life sciences, energy, environmental technology, cultural heritage, fundamental physics, and Materials Science and Engineering.
In Materials Science and Engineering, neutron scattering provides complementary information about the composition, phases, microstructure and stresses in materials under ambient conditions, as well as a function of some external parameters such as temperature, pressure, or applied load, extending into alloy development, materials processing, joining technology, and gives engineers and materials scientists a unique insight into components used in e.g. aerospace or power generation industry.
ESS will be well suited for in-situ studies due to high neutron intensity allowing for specialised sample environment in combination with a wide range of scattering techniques such as diffraction, imaging, or small angle scattering. Areas of research may include
investigations of thermo-mechanical treatments
near-surface measurements and effects of surface treatments such as peening
microstructural studies e.g martensitic TRIP steels
precipitation hardening of super alloys
phenomena such magnetic domain structure in steels
texture phenomena and their impact on materials properties
addressing the continuously increasing need to understand properties of newly designed materials. While the European community is developing and proposing dedicated instruments for ESS building sophisticated instruments has to go hand-in-hand with detector development, better optical systems and improved shielding, and advancements in computing. Combining design efforts with technology and data analysis will provide insight into new design possibilities, and help understanding new phenomena not only in the area of Material Science and Engineering but generally in all areas of the natural sciences.
The current status of the ESS and future opportunities will be presented with a focus on Materials Science and Engineering applications.
References
[1] ESS Technical Design Report, April 23 (2013), ESS-doc-274,
ISBN 978-91-980173-2-8,
http://esss.se/documents/tdr/TDR_final.pdf

Synchrotron x-ray radiation was used for in situ strain measurements in thin films on polyimide substrate during biaxial deformation tests [1]. We have used an area detector that allows inspecting multiple directions in the polycrystalline thin film without serial sectioning during straining i.e. time-resolved x-ray strain measurements. The configuration used and the attainable orientations are placed on pole figures for which the x-ray strains are measured. Both x-ray diffraction and digital image correlation are employed to monitor the substrate and film strains during complex loading path. The experimental approach allows for scrutinizing strain partitioning at substrate-film interface as well film inelastic onset. In fact, we have been able to extract the yield surface of W-Cu nanocomposites and demonstrate its brittle behavior [1]. More recently, {111} and {200} strain pole figures (SPF) of an ultra thin Au layer could be monitored simultaneously upon loading. This offers insight into ultra-thin film anisotropic response under complex biaxial loading [2]. Further developments and perspectives will be discussed.
[1] S. Djaziri, D. Faurie, P.O. Renault, E. Le Bourhis, P. Goudeau, G. Geandier, D. Thiaudière, Acta Mater. (2013) 61, 5067.
[2] G. Geandier, D. Faurie, P.-O. Renault, D. Thiaudière, E. Le Bourhis, J. Appl. Cryst. (2014) 47, 181

We present a novel system of slits, called spiderweb slits, for depth-resolved high energy x-ray powder diffraction experiments. The slits select diffracted x-rays from a gauge volume of a sample while greatly attenuating diffracted x-rays from other sources in the path of the x-ray beam. This capability can be used to block diffraction from battery cell containers, reaction cell windows, or pressure cell windows, thus enhancing many in-situ experiments. High energy x-rays in combination with the depth resolution provided by the spiderweb slits can provide information from specific locations within a polycrystalline material under standard conditions or while working under mechanical, chemical or electric load or extreme conditions. The spiderweb slits function similarly to conical slits or spiral slits, but in this design, select large azimuthal fractions of the Debye-Scherrer diffraction cones for any possible diffraction cone over the area of the slits, while preserving the integrated diffraction peak relative intensities and peak widths, greatly improving performance and versatility compared to previous slit systems. The first slit prototype was applied to several experiments at the X17A beamline at the National Synchrotron Light Source, and these results are presented and compared with ray-tracing simulations. The spiderweb slits will be utilized at the National Synchrotron Light Source II X-ray Powder Diffraction (XPD) beamline.

Most of the knowledge on mechanical behaviour of engineering materials has been derived from conventional uniaxial tensile or compression tests. However, in real-life applications the stress states are usually far more complex. During typical processing routes materials often are subjected to multi-axial strain paths and/or strain path changes. There is general awareness that such complex stress/strain states are important, but relatively little is known about the underlying mechanisms.
The neutron time-of-flight diffractometer POLDI (SINQ, Switzerland) has implemented a unique mechanical test rig for in-situ studies during multi-axial deformation. Cruciform shaped specimens are deformed under in-plane non-proportional loading conditions, while recording neutron diffraction patterns, providing information on the developement of inter- and intragranular strains.
In this work we study the developement of intergranular strains during biaxial straining of various metals and compare it with the known case of uniaxial deformation. We find that both the nature and magnitude of the intergranular strains are strongly affected by the loading conditions. Furthermore, we have performed various strain path changes with and without intermediate unloads. The evolution of lattice strain provides insights into how residual strains are built-up depending on the straining history. Also, by tracking the evolution of the peak broadening we find signatures for recovery mechanisms during a change of strain path.

Complex hierarchical microstructures spanning multiple length scales are common in functional materials today and are likely to become more prevalent in the future. The development and optimization of these materials require powerful structure characterization tools with capabilities matching the complexity of the problem. A versatile materials microstructure and structure characterization facility at the Advanced Photon Source (APS) strives to provide such capabilities by combining Bonse-Hart ultra-small-angle X-ray scattering (USAXS) with pinhole SAXS and wide-angle X-ray scattering (WAXS) measurements. Making use of Si 440 crystal optics and high-energy X-rays, this unique combination provides characterization capabilities over 5 decades in scale range - from over 20 micrometers as an upper length scale down to below 1 Å. The maximum allowable feature size matches that of contemporary ultra-small-angle neutron scattering (USANS) instruments, while the X-ray flux of 10^12-13 photons/second enables rapid in situ measurements. Recent implementation of on-the-fly scanning of the USAXS instrument allows complete characterization over this entire size range in under 3 minutes.
Multiple additional capabilities have been developed recently and are now available to the user community:
USAXS-XPCS: Taking advantage of the coherence in the X-ray beam and using a 2D collimated USAXS geometry, the internal dynamics of materials can be studied with millisecond time resolution by X-ray photon correlation spectroscopy (XPCS) in USAXS-XPCS measurements over a microstructure scale range from asymp; 100nm to several micrometers.
USAXS Imaging: The capability to characterize large microstructural features, within a field of view of asymp; 1 mm with 1 µm spatial resolution is achieved in transmission-geometry USAXS imaging where the USAXS crystal analyzer is set to specified momentum transfer values, Q.
Future plans: The planned APS upgrade to incorporate a multi-bend achromat (MBA) storage ring design will provide significant improvement in X-ray beam coherence and brightness. This will result in major advances in USAXS-based techniques, especially in USAXS-XPCS and USAXS imaging. Current plans for the existing facility included development of USAXS imaging tomography to provide 3D characterization capabilities with asymp; 1 µm resolution and 1 mm field of view.
Meanwhile, to meet a growing demand for in-operando/in-situ studies, increasingly sophisticated “non-X-ray” measurement capabilities are being developed to allow the user to characterize materials microstructure and/or structure, and materials properties and/or performance simultaneously. In this context, specific sample cell geometries can be designed through collaboration between users and APS staff, and then manufactured at the APS.
The presentation will review the current status of this versatile materials characterization facility and present scientific examples enabled by its unique capabilities.

The synchrotron radiation source provides an intense, tunable, monochromatized, and well-collimated X-ray beam that is ideal for imaging technique. In this work, the synchrotron-based K-edge subtraction imaging technique was developed to quantify the spatially resolved element distribution of the sample. By scanning samples at energies just above and below the Zn K-absorption edge and subtracting digital images of such observations, the quantitative distribution of Zn in a closed cell Al-Zn-Mg foam was determined. Some other microstructural features, such as content, size distribution, shape and spatial distribution of micro-pores inside the cell wall, were also obtained using three-dimensional quantitative image analysis of the tomographic dataset. The evolution of these microstructural features was assessed during the heat treatment process. With the combination of synchrotron-based X-ray microtomography and K-edge subtraction technique, the cell wall damage behavior of the Al-Zn-Mg foam were investigated. The current techniques show great promise for the microstructural analysis in the foam materials.

Tetragonal iron selenide (β-FeSe) adopts the simplest crystal structure of the recently-discovered iron-based superconductors, and is of considerable interest for the development of the structure-properties relationship. Conventional solid state syntheses produce samples with superconducting transitions near 8 K, though these methods require extended treatment at high temperatures and are undesirable for large-scale applications. Additionally, many of these samples have homogeneity ranges, and include various impurity phases. Several low-temperature solution-based syntheses have been reported, though samples produced by these methods exhibit antiferromagnetic ordering instead of superconductivity. We have developed a solvothermal method to synthesize phase-pure β-FeSe from elemental precursors at low temperatures (200 °C). We have shown how the superconductivity can be triggered in those samples depending on the synthetic conditions. Characterizations of the superconducting and non-superconducting samples by means of synchrotron X-ray powder diffraction and neutron diffraction pair distribution function (PDF), TEM, and ⁵⁷Fe Mössbauer spectroscopy reveal complex interplay between Fe vacancy formation, incorporation of the interstitial hydroxyl groups, structural distortion, and superconductivity.

Development of novel accelerator -driven compact neutron source system on-site for industrial use and human resources has initiated in RIKEN from 2012 and the neutron beam has been available from April of 2013. The world&’s first visualization of under film corrosion of different kind of steels with RANS (RIKEN Accelerator-driven compact Neutron Source) has accomplished with the ISIJ (The Ion and Steal Institute of Japan) Research Group of “Characterization of microstructure in steels by compact neutron source Feasible Study” successfully. This research experiment was proposed and the corrosion samples have been offered by Dr. T.Nakayama of KOBELCO. The difference of corrosion growth between normal steel and alloy steel was also observed. It indicates that the latter has better corrosion resistance than the former. This result is believed to serve as an improvement of corrosion life of painted steel structures, and usefulness of compact neutron source.
The large area fast neutron imaging detector has been developed and we succeed to distinguish among three steel bars existence in 30cm thickness concrete. It is promising technology for the health diagnostic system with transportable neutron source and with the health diagnostic simulation technique which is developing now.

Since the start of this year, the new XPP/KMC3-Beamline dedicated to time-resolved X-ray diffraction and EXAFS experiments is available at the Bessy II synchrotron in Berlin. A special feature of the beamline is a fiber based 250 fs pulsed laser system that is synchronized to the x-ray bunch pattern. The laser operates at high repetition rate up to 1.25 MHz.^[1] Thus, using the Bessy II camshaft pulse, ultrafast pump-probe measurements with a time resolution of 100 ps in the standard hybrid mode and 10 ps in the low-alpha mode are possible. The beamline provides either monochromatized X-rays in the range of 2-12 keV or a white beam which covers the full beamline spectrum.^[2]
Full user operation is expected to start at the beginning of 2015. In the meantime, further upgrades of the detection system and of the sample environement are planned: A gated Pilatus 100k hybrid pixel area detector allows for two-dimensional static and time resolved measurements. Combined with a new 3+1 circle goniometer a large reciprocal space volume can be covered. The sample temperature can be controlled down to 90 K using a cryogenic nitrogen jet. For even lower temperatures down to approximately 20 K a UHV vacuum chamber and a cryostat will be available at the end of this year. In addition, a new set-up implementing recent successful results for the shortening of hard x-ray pulses with laser excited nanostructured materials will be presented.^[3] It is planned to further improve and realize this so called PicoSwitch as an available operation mode at the XPP/KMC3 beamline.
To demonstrate the beamline performance selected experiments on nanostructured solid state systems will be presented. A special focus for pump-probe experiments at high repetition rates lies on managing the thermal laser heat load in the sample.^[4] In addition, results on coherent phonon dynamics and magnetostriction in laser-excited Holmium will be given as an application of ultrafast pump-probe measurements at low temperatures.
[1] H. Navirian, R. Shayduk, W. Leitenberger, J. Goldshteyn, P. Gaal and M. Bargheer, Synchrotron-based ultrafast x-ray diffraction at high repetition rates , 2012, Rev. Sci. Instrum., 83, 6, 063303
[2] http://www.helmholtz-berlin.de/forschung/oe/funkma/ultrafast-dynamics/research/beamline_en.html
[3] P. Gaal, D. Schick, M. Herzog, A. Bojahr, R. Shayduk, J. Goldshteyn, H. A. Navirian, W. Leitenberger, I. Vrejoiu, D. Khakhulin, M. Wulff and M. Bargheer, Ultrafast Switching of hard X-rays , 2014, J. Synchrotron Rad., 21, 2, 380--385
[4] H. A. Navirian, D. Schick, P. Gaal, W. Leitenberger, R. Shayduk and M. Bargheer, Thermoelastic study of nanolayered structures using time-resolved x-ray diffraction at high repetition rate , 2014, Appl. Phys. Lett., 104, 2, 021906

Substrate-mediated gene delivery has generated much interest due to its ability to concentrate genes at the site of interest for localized gene delivery. This localized gene delivery has the potential to improve gene transfection efficiency compared to conventional solution-based methods because cells adhere onto the surfaces where gene vectors are incorporated, resulting in higher exposure and local concentration. In addition, with the rapidly expanding technology of bioelectronic devices, it is crucial to understand and develop delivery techniques from hard/soft material platforms.
Most studies of substrate-mediated gene delivery have utilized polymer-based systems. Lipid-based delivery, however, is largely unexplored. While polymers have the advantage of tailored surface chemistry to control adhesion to the surface, lipids offer better biocompatibility, 2D nanostructure, and directional diffusion. Moreover, recent techniques to control adhesion and leakage are giving new potential to substrate-mediated delivery using lipid materials.
In this work, we prepared and characterized self-assembled siRNA-lipid films and used them for in vitro siRNA delivery. Thin films of lipid liquid crystalline phases on solid surfaces were prepared by spin-coating and three different nanostructures-cubic, hexagonal and lamellar-were obtained. We will show the structural details of the films investigated by polarized microscopy, atomic force microscopy, and grazing incidence small/wide angle X-ray scattering (GISAXS/GIWAXS) and show how the different materials vary with respect to efficiency of siNRA mediated gene knockdown.

Coherent x-ray micro-diffraction was used to detect and count phase defects (stacking faults, SFs, left in the crystal after the glide of partial dislocations) preliminarily introduced by deformation of InSb single-crystalline micro-pillars. Diffraction patterns were recorded by scanning the coherent micro-beam along the pillars axis: peak splitting is observed in the diffraction pattern associated to the top region, in agreement with the presence of a few SFs located in the upper part of the deformed pillars. Simulations of coherent diffraction patterns were also performed considering SFs randomly distributed in the illuminated volume: they show that not only the number of defects but also the size of the defected volume influences the maximum intensity of the pattern, allowing for a precise counting of defects.
Similar diffraction measurements were performed in-situ, during compression, to detect the first lattice defects, i.e. the first events of the plastic deformation appearing in InSb micro-pillars.
Physical Review Letters, 111 (2013), 065503

The Quantum Beam Science Center of Japan Atomic Energy Agency (JAEA) is promoting a wide variety of science and technology by multiplex and complementary use of various quantum beams from the JAEA-owned large-scale facilities and instruments. These are high-intensity and high-quality photons from J-KAREN laser facility in Kizu, synchrotron radiation from SPring-8 beam-line facilities in Harima, neutrons from JRR-3 research reactor and J-PARC/MLF spallation source in Tokai, electrons and ion beams from accelerator facilities in Takasaki. The research activities cover wide areas from basic and applied sciences to industrial applications relevant for environment and energy, materials, life science and biotechnology.
In this talk the R&D of the Quantum Beam Science Technologies at JAEA will be presented with an emphasis on materials exploration with neutrons and synchrotron x-rays. Discovery of NaCl-type lanthanum monodeuteride under high pressure by complementary use of synchrotron x-rays and neutrons, in-situ load experiment on residual stress in reinforced concrete using neutrons, utilization of polarized neutrons in magnetic materials imaging and spin contrast variation technique for soft matter will be reported.

Thickness-dependent Pendellösung oscillations as described in the dynamical theory of diffraction are highly sensitive to strain fields from defects in a host crystal. Based on this, we initiated a novel approach to determine the precipitation kinetics of oxygen in silicon (Si) at the early stages of clustering at high temperatures and present in-situ X-ray measurements up to 900 °C performed with the characteristic K_α1-line at 59.31 keV. By using wedge shaped samples the thickness-dependent diffraction data can be collected over several orders of Pendellösung oscillations with a single exposure and without any mechanical motion giving the data an extreme sensitivity to minute changes in the diffraction pattern. The in-situ data can be interpreted in the framework of the statistical dynamical theory of X-ray diffraction. This evaluation yields the static Debye-Waller factor E with annealing time. E is directly correlated to the strain introduced by growing SiO_x nanoprecipitates. Because of the high sensitivity the technique of in-situ Pendellösung measurements allows to follow the precipitation behavior from early stages onwards to adult precipitates. The data is further interpreted within a diffusion limited model of growing spherical precipitates.
We present an investigation on moderately p- ([B] asymp; 10¹⁵ 1/cmsup3;) and highly p+ ([B] asymp; 10¹⁸ 1/cmsup3;) boron doped Czochralski Si crystals at different nucleation and growth temperatures to determine the nucleation and precipitation kinetics as well as the long time precipitation behavior. We found enhanced nucleation rates in p+ material at 450 °C and 780 °C as compared to the p- samples. Whereas the acceleration at 450 °C can be explained with boron enhanced oxygen dimer diffusion, the nucleation rate at 780 °C is much too high to be accounted for by the enhanced oxygen dimer diffusivity alone. Moreover an analysis of the misfit strain yields platelet morphology of the precipitates with a higher aspect ratio in the p- than in the p+ case. In addition, Transmission Electron Microscopy was used as a complementary method validating the results of in-situ Pendellösung measurements.
In addition, two growth regimes were identified. An initial diffusion driven growth process is followed by a long time precipitation behavior of comparable amplitude in both materials. This regime can be interpreted as Ostwald ripening and gives access to the surface energy of the precipitates.

Abstract: The work presents a comparative study on the AlGaN/GaN type-II heterostructures grown on c-plane sapphire (Al₂O₃) and Si (111) by Plasma Assisted Molecular Beam Epitaxy (PA-MBE). The in depth structural characterizations of these samples were performed by High-Resolution X-Ray Diffraction (HRXRD), X-ray Reflectivity (XRR) and Field Emission Scanning Electron Microscopy (FESEM). On the basis of HRXRD measurements, the stress-strain of the layers was examined. The c- and a-lattice parameters of the epilayers as well as in-plane and out-of plane strains were determined from the omega;-2theta; for symmetric scan and omega;- Xtheta; (X represents the coupling coefficient) for asymmetric scan. Strain, tilt and correlation lengths were calculated from Williamson-Hall (W-H) plots. Moreover, the twist angle was measured from skew symmetric scan of (102), (103), and (105) plane along with (002) symmetric plane by fit with model of Srikant et al. The composition and strain/relaxation state of the epilayers were observed in details by reciprocal space mapping (RSM). The symmetric (002) triple axis RSM (TARSM) and asymmetric (105) double axis (DA) RSM of grazing incidence (GI) were carried out on each sample. The defect density were measured from HRXRD curves of skew symmetric (002) and (102) reflection plane. The Al mole fraction and strain states of the layers were calculated by fitting the experimental curves with computer simulations and compared with theoretical findings based on elastic theory. The thicknesses of the layers and roughness of the interfaces were measured from simulation of the nominal structure by fitting with XRR experimental curves.
The Ga(Al) terminated GaN/AlGaN/GaN on Al₂O₃ and Si (111) substrate were grown by plasma assist molecular beam epitaxy. The solid sources were used for Al and Ga on the other hand die nitrogen (N₂) is used as a plasma source for nitride element. The (002) omega;-2theta; scan shows the presence of GaN, AlGaN and AlN layer of proposed heterostructure. The XRR and cross sectional FESEM image confirm that the thickness of individual layer for GaN/ AlGaN on Al₂O₃ heterostructure with AlN nucleation layer are GaN=1.2 mu;m, AlGaN=20 nm ,GaN cap = 3 nm and AlN = 20 nm. For GaN/AlGaN/GaN on Si (111), the thickness of individual layer are GaN cap =3 nm, AlGaN = 20 nm, GaN channel = 1.2 mu;m, and AlN/GaN/AlN stack for buffer layer are 0.23 mu;m, 0.27 mu;m and 0.05 mu;m respectively. The measured Al mole fraction is 30 % for both structure which were measured from peak separation between GaN and AlGaN and also fit with simulations. The details HRXRD analysis shows from RSM that AlGaN layer exhibit pseudomorphic in nature on the other hand GaN layer is nearly relaxed, only residual strain is present for different thermal expansion coefficient between epilayer and substrate. The screw and edge defect density were measured from FWHM of skew symmetric scan of (002) and (102) plane respectively.

In this presentation the sampling and intensity statistics of X-ray diffraction data obtained from polycrystalline nanopowders are discussed. It is shown that the very large acceptance angles of crystalline nanoparticles can invalidate some classical assumptions made in computing the number of diffracting grains scattering into a given Bragg reflection.It is suggested that formulations previously tested and verified for polycrystalline aggregates with grains larger than 500 nm should be revalidated for particles with coherent scattering lengths below 10 nm.

Serial femtosecond crystallography of protein crystals at X-ray free-electron laser facilities typically requires liquid sample delivery methods based on jets or drops to bring new undamaged crystals to the region of interaction with X-rays. The maximum rate at which the crystals can be supplied, and thus the data acquisition rate, is limited by the rate at which the flow of liquid recovers after single-shot diffraction experiments.
We have imaged optically the damage process in water microjets due to intense hard X-ray pulses at LCLS, using high-speed imaging techniques to record movies at rates up to half a billion frames per second. For pulse energies larger than a few percent of the maximum pulse energy available at LCLS, the X-rays heat the jet to temperatures much larger than the boiling temperature, and induce a phase explosion that opens a gap in the jet.
The LCLS pulses last a few tens of femtoseconds, and the thermalization of water is expected to be completed in a few picoseconds; the full evolution of the broken jet, however, is orders of magnitude slower - typically in the microsecond range - due to a complex fluid dynamics process triggered by the phase explosion. For example, we observed the formation of water films that can fold back and impact the jet, causing further damage to the jet and increasing the jet recovery time. The microsecond recovery times we observed present a limitation to experiments planned at future high-repetition rate XFEL facilties.
We will comment on the possible solutions to reduce the jet recovery time to sub-microsecond regime, and report on our progress in modeling the jet explosion dynamics, towards the goal of semi-quantitative prediction of jet recovery times.

Pair distribution function (PDF) measurements have originally been used to study the structure of liquids and glasses [1]. Almost forgotten thereafter, the method experienced a tremendous revival as Rapid Acquisition PDF with large, fast-read out 2D detectors at dedicated high-energy beamlines [2]. The recent interest focusses on disordered materials such as nanoparticles [3] and in-situ studies of chemical processes, where common x-ray diffraction fails [4]. The current state-of-the-art of the technique is the application in nanoparticle nucleation in liquid media [5]. Within our recent in-situ experiments we followed the formation of zinc oxide (ZnO) nanoparticles from molecular-like precursors at zinc concentrations of less than 30 mM in ethanol, which is one order of magnitude less than concentrations in other reacting systems published so far [5, 6]. Upon the addition of a base, e.g. the organic base tetramethylammonium hydroxide, the nucleation process of the nanoparticles is induced. The precursors react to 1.3 nm large magic-sized clusters of wurtzite structure, i.e. already the final bulk crystal structure. These metastable magic-sized clusters persist in solution for surprisingly long periods of time. Once a sufficiently high supersaturation is reached they undergo oriented attachment to form 2.5 nm large spherical particles, which do not further grow. By adding different organic ligand molecules at the start of the synthesis, we can furthermore change the reaction kinetics and influence the reaction pathways.
In conclusion, we could demonstrate for the first time that non-classical nucleation pathways follow a non-continuous stepwise growth that includes highly crystalline magic-sized clusters. In a way, our experiments go back to the roots of PDF measurements, as the overwhelming signal in our data stems from the solvent. Nevertheless we do observe a restructuring process of the nucleating clusters even at concentrations of less than 0.5 wt%.
[1] Zachariasen, W. H., J. Chem. Phys. 3 (1935), 158
[2] Chupas, P. J., Qiu, X., Hanson, J. C., et al., J. Appl. Cryst 36 (2003), 1342-1347
[3] Korsunski, V. I., Neder, R. B., Hradi, K., et al., J. Appl. Cryst. 36 (2003) 1389-1396
[4] Borkiewicz, O. J., Chapman, K. W., Chupas, P. J., Phys. Chem. Chem. Phys. 15 (2013) 8466-8469
[5] Jensen, K. M. O., Christensen, M., Juhas, P., et al., J. Am. Chem. Soc. 134 (2012), 6785-6792
[6] Hu, Y.-J., Knope, K. E., Skanthakumar, S., et al., J. Am. Chem. Soc. 135 (38) (2013), 14240-14248

Diffraction methods of analysis have undergone continuous development in the past 100 years. As we celebrate the International Year of Crystallography we can appreciate the contributions of several generations of scientists in continuously developing next generation hardware, software, and analysis methods. Diffraction is a “fingerprint” method whereby identification and microstructural characterization is performed by comparison to reference materials. Both the reference materials themselves and the methods that use these materials have had to keep pace with modern methods of analysis. In this presentation we will compare the evolution of diffraction hardware and software and the corresponding requirements in the development of reference databases and methods of analysis by The International Center for Diffraction Data (ICDD) and its membership of international scientists.
The modern Powder Diffraction File is a relational database containing hundreds of millions of pieces of data organized in tables. Embedded software contains numerous searches, display fields, analysis tools, and simulations, that provide extensive data mining and tools to enable the user to identify, quantitate and characterize materials. In the last decade we have expanded the database from a collection of crystalline materials to reference solid state materials by the inclusion of polymers, clays, amorphous materials, and nanomaterials. With the growth of worldwide synchrotron and neutron user facilities we have added capabilities to analyze neutron and synchrotron data. New analysis tools have been developed to study nanomaterials. Methods have been developed to study, index and visualize the multidimensional lattices and super spacegroups found in modulated structures. Overall as the science continues to progress we are performing more sophisticated analyses at increasingly lower detection limits. As we progress into the future we will continue to evolve to address the needs of global scientists.

Nanocatalysts derived by alloying noble metals with other transition metals at the nanoscale exhibit enhanced catalytic and electrocatalytic activities for many reactions in energy production, conversion and storage in comparison with pure noble metal catalysts, which have attracted a great deal of interest from the perspectives of cost reduction and materials sustainability. However, the understanding of the structural-catalytic synergy remains to be a major challenge for the rational design of catalysts, which will call for breakthroughs of advancements in both multifunctional nanomaterials and characterization techniques. This report describes recent findings of an investigation of noble metal (Pt and Pd) based binary and ternary nanoalloy nanocatalysts for carbon monoxide oxidation reaction using synchrotron X-ray based ex-situ and in-situ high-energy XRD (HE-XRD) technique (S Shan, et al, J. Amer. Chem. Soc., 2014; L Yang, S Shan, et al, J. Amer. Chem. Soc., 2012). One example involves PdNi binary catalysts, for which an intriguing catalytic synergy was discovered for the composition ratio of Pd:Ni at 50:50. The detailed correlation with surface coordination numbers and surface interatomic distances is established using HE-XRD coupled to atomic pair distribution function analysis (PDFs) and reverse Monte Carlo simulation. The atomic-scale alloying state and lattice change revealed by in-situ HE-XRD/PDFs monitoring of the structural evolution and phase transitions of the nanoalloys in the oxidative - reductive processes and the 3D modeling of the data provided new insights for assessing the structural-catalytic synergy. These findings will be discussed, along with their implications for the design of nanoalloy catalysts for applications in sustainable energy production, conversion and storage.

With current technology moving rapidly toward smaller scales nanometer-size alloys are being produced in increasing numbers and explored for various useful applications, in particular catalytic ones. To understand better and so gain more control over the performance of nanoalloy catalysts, precise knowledge of their atomic-scale structure is needed. With bulk alloys such knowledge is almost straightforward to obtain by Bragg x-ray diffraction (XRD). Unfortunately, Bragg XRD is inapplicable to nanoalloys since their XRD patterns show a limited number of distinct Bragg peaks, if any, and a very pronounced diffuse component. The problem can be solved by employing a non-traditional approach involving high-energy XRD and atomic pair distribution functions (PDF)s analysis ¹. However, for a nanoalloy comprising n atomic species a single XRD experiment yields a total atomic PDF which is a weighted sum of n(n+1)/2 partial PDFs. This could make the interpretation of PDF data for nanoalloys ambiguous. Using resonant high-energy XRD allows particular partial PDFs to be highlighted and others dimmed thus giving very much needed chemical specificity ^2-4. In the talk we will briefly introduce resonant high-energy XRD as applied to atomic PDFs analysis and give examples from several recent studies on nanoalloy catalysts of Au-Pt, Au-Cu, Pt-Pd and Pt-Ru families, including building 3D structure models on the basis of total and partial atomic PDFs, and using the models for rational consideration of nanoalloy structure-catalytic properties relationship.
1. V. Petkov, Materials Today 11 (2008) 28.
2. V. Petkov and S. Shastri, Phys. Rev. B 81 (2010) 165428.
3. V. Petkov et al., Nano Lett. 12 (2012) 4289.
4. V. Petkov et al., J. Phys. Chem. C 117 (2013) 22131.

Titanium diboride (TiB₂) is a high strength ceramic which is considered for use in military armor applications. It is an excellent electrically and thermally conductor. However, TiB₂ as a highly covalent ceramic is very challenging to sinter to high density while suppressing its oxidation at high temperatures. In this study, the effects of simultaneous electric and thermal fields on densification of TiB₂ nanoparticles of 58 nm median diameter were studied using in situ time-resolved in-situ high temperature EDXRD with a polychromatic 200 keV synchrotron probe. Firstly, we report on the oxidation process in TiB₂ in the temperature RT-600 °C range with no applied electric field where no oxidation was observed. Secondly, we report on effects of electric field over the same temperature range were we observed a sharp increase in the apparent conductance of the system 330 °C under 4.44 V/mm. The current draw at this point reached 10 A and stayed stable. Both experiments were carried out in Argon gas flowing under 4 psi pressure. We observe an electric field facilitated oxidation of TiB₂ at <600 ^oC. The oxidation process under applied electric field yields TiBO₃ peaks almost instantaneously. A shift in the pattern is also observed during current draw which is indicative of unit cell dilation due to charge transport. The origins of such current induced unit cell expansion will be discussed within the framework of tunneling phenomena at particle-particle contacts.

DPC Toolkit is an easy-to-use computer program designed to help users identify a crystal structure that is consistent with their 2D GIWAXS data. Although several programs can help users identify crystal structures from single-crystal or powder diffraction data, few computational tools can process X-ray diffraction data collected directly on polycrystalline thin films. Yet, understanding the structure of these films is crucial to their optimization because they often represent the active layers of organic opto-electronic devices. Our program requires few inputs -- the user can easily process their diffraction image from data collected with any position-sensitive detector, and the user need only to make few preliminary assumptions about the crystal structure prior to analysis. Our program does not account for structure factors since they require knowledge of the occupied lattice positions. Instead, the user may select specific space groups to eliminate the calculation of reflections that are forbidden due to unit cell symmetry. Since thin films often exhibit out-of-plane orientation, the user specifies the unit cell plane that is parallel to the substrate. The user also specifies the range of the Miller indices of reflections and the range of the unit cell lattice parameter values. The user can choose either Manual or Automatic modes of operation. In Manual mode, the user can visually match the positions of the experimental and calculated reflections by individually tuning the unit cell parameters with sliders. In Automatic mode, the program performs this process for the user by identifying the positions of the experimental reflections and tuning the unit cell lattice parameters to best match the calculated reflections with the experimental ones through a “boundary-tightening” algorithm that utilizes the positions of key experimental reflections to place physical constraints on the possible range of unit cell dimensions. To demonstrate the use of this program, we take the user step-by-step though refining the thin-film structure of 5,11-bis(triethylsilylethynyl)anthradithiophene, TES ADT, and solving the thin-film structure of a fluorinated, contorted hexabenzocoronene, 16F-HBC.

Disordered tellurides have been source of important applications and intense research. There are seen as promising materials for phase-change memory devices [1] and infrared transmitting waveguides [2]. For both applications the disordered phases (liquid and amorphous) play a crucial role since they are involved either in the fabrication process or in the functioning of the devices. In the case of phase change materials, the data storage is based on the differences in optical and electronic properties between crystalline and amorphous phases. While crystalline phases have been the subject of a huge number of studies, much less is known on the liquid state though it is involved in both amorphization and recrystallization processes in the devices. Amorphization is achieved by quenching the liquid, while the fast recrystallization of amorphous regions takes place above the glass transition, through the under-cooled liquid state. Therefore, in-depth understanding of the structure of the liquid state could contribute to the understanding of both processes occurring during the data storage. Moreover, recent works have shown that the liquid structure is a useful starting point to describe the amorphous phase [3,4] in the case of phase-change alloys.
In this contribution we present a combined structural and vibrational study of three Tellurium based liquids. The chosen alloys belong to the binary Ge-Te and the ternaries Ge-Sb-Te and Ge-Ga-Te systems since they are good candidates for phase change memory and infrared transmitting waveguides. Neutron diffraction and inelastic experiments were performed for each system at three compositions and two temperatures in the liquid state. Such a systematic study allowed studying both temperature and concentration trends as well as the substitution effect between Antimony and Gallium. The experimental study is accompanied with density functional based molecular dynamics simulations including dispersion forces. The latter have been recently shown to give a substantial improvement of the simulated structures [5,6]. The combination of experiments and simulations allows a complete description of the structural properties in the liquid state. Structure factors, radial distribution functions, coordination numbers, neighbors, angular and rings distributions in terms of partial contribution are presented. The vibrational properties illustrated by the vibrational density of states are also computed and compared to the experimental data.
[1] Phase Change Materials and Applications, ed. by S. Raoux, and M. Wuttig, Springer, Berlin, 2008.
[2] S. Danto et al . Adv. Funct. Mater. 16, 1847 (2006).
[3] C. Steimer et al. Adv.Mater. 20, 4535 (2008).
[4] A.V. Kolobov, et al. App. Phys. Lett. , 95, 241902 (2009)
[5] M. Micoulaut, J. Chem. Phys. 138, 061103 (2013).
[6] M. Micoulaut et al. Phys. Rev. B. 89, 174205 (2014)
Acknowledgments :
Support from Agence Nationale de la Recherche (Grant No ANR-11-BS08-0012) is aknowledged.

Modern diffraction and scattering methods of X-ray radiation allow for multi-dimensional insight into material morphology for both polymer-based composite films and fibers. These approaches and analysis tools can be used to probe the makeup of individual grain structures in various polymer nano-composite materials in order to examine the effects of the fillers on nano-scale structural changes in composites. The electron intensity correlation function, derived from Fourier transformations of the X-ray scattering pattern provides a path to analyze acquired scattering data for space resolved domains. Here in this study, polymer-based nano-carbon composite systems are analyzed. The polymers used include polyvinyl alcohol, polyethylene, and polyacrilonitrile as matrix materials. The nano-carbon filler contribution to the grain size evolution is tracked by X-ray scattering/diffraction characterization. These morphological features and their relationship to the mechanical reinforcement efficiency of the filler are also discussed. These results show that the relevant sizes of crystalline and amorphous domains within the lamellae structures correspond to the dispersion/distribution of the nano-filler in the composite materials. This work also illustrates an effective use of the correlation function to provide global morphological analysis toward understanding the ability of nano-fillers to influence polymer structural evolution in the composite system.

The dynamical theory of diffraction as developed for perfect crystals in the early 20^th century provides an excellent description of experimental Bragg intensities and line shapes. However, a full dynamical approach for the practically relevant case of crystals showing deviations from perfect crystallinity by dislocations or point defect agglomerations was published only very recently [1], about 100 years later. As a result, the entire Bragg profile including the diffuse intensity induced by lattice imperfections can now be understood quantitatively yielding a precise picture of defect geometries and concentrations.
Czochralski-grown semiconductor-quality silicon contains some 10¹⁷ cm^-3 atoms of interstitial oxygen incorporated during crystal pulling. Being in a supersaturated solid solution at lower temperature, the oxygen forms clusters upon thermal treatments at temperatures exceeding 800 °C. Such precipitates have been investigated extensively with various methods including infrared light scattering and TEM because of their relevance for internal gettering, a fundamentally important process for the engineering of modern highly integrated circuits.
Due to their volume misfit with the host lattice the precipitates distort the otherwise highly perfect silicon matrix and thus become visible in X-ray diffraction albeit a low concentration of 10¹⁰ cm^-3. High resolution synchrotron X-ray data taken at the 400 reflection of samples after heat treatment show diffuse scattering from the strain fields of the nanoprecipitates, and their evolution with annealing time allows a quantitative description of the size increase. TEM measurements confirmed quantitatively these findings.
A special aspect is the in-situ capability of our X-ray experiments carried out at temperatures up to 1165 °C. The repetitive measurement of rocking curves at high temperatures allows to follow in real time the growth of the nanoprecipitates with a resolution of 0.5 h providing a unique access to the growth kinetics.
[1] Molodkin et al., Phys. Rev. B, Vol. 78, 22, 224109 (2008)

Crystals of the family of crystallographic Tutton salt A₂B(XO₄)₂.6H₂O, A=K, NH4, Rb, Cs, Tl, B=Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd, V, Cr, X=S e Se has been investigated by various experimental techniques in order to understand their physical properties and potential technological applications [1]. Investigations on the structural stability have been performed by x-ray diffraction and in order to understand their structural properties, mainly the Jahn-Teller distortion present in the crystals with chromium and copper [2, 3]. This distortion arises when an unpaired electron, e ore eg, transition metal causes a stretching or a contraction of one or more of the principal axes of the coordination layer. Solid solutions of these salts in the form A₂B'_xB”_(1-x)shy;(SO₄)₂.6H₂O has been relatively little investigated although Jahn-Teller distortion present. The crystal structure of this series at room temperature is monoclinic, space group P21/a with two molecules per unit cell. The B ions are surrounded by six water molecules forming a distorted octahedron that originates when the Jahn-Teller distortion. The B ions are two points of coordinates (0,0,0) and (0,1/2,1/2) and the four ions within the cell. The structure has a strong network of hydrogen bonds is probably the reason so many compounds have the same crystallographic arrangement.
The paper presents results of crystal growth series (NH₄)₂Ni_xCu_(1-x)(SO₄)₂.6H₂O with 0 Atomic force microscopy (AFM), from these crystals. Good single crystals of this family were obtained over the entire range of composition, though for higher concentrations of copper crystals are milky appearance. Data x-ray diffraction, the powder method, revealed that the structure of the samples with x around 0.5 is presented with strong distortion when compared with those of low or high values of x.
References:
[1] Voigt, W., Goring, S., Thermochimica Acta, 237, p. 13, (1994).
[2] Zhan Chen, Suli Fei, Strauss, H. L., J. Am. Chem. Soc., 120, p. 8789, (1998).
[3] Dobe, C., et al., Inorg. Chem., 42, p. 8524 (2003).
Acknowledgment: FAPEMIG; CNPq; UFOP.

In this presentation we will show how the K-factor approach after B.H O&’Connor & M.D. Raven¹, build into HighScore Plus 4.0, can elegantly be used to quantify amorphous material in complex samples without contamination of the sample by adding an internal standard. We will demonstrate the ease and accuracy of this method to quantify amorphous content by showing several complex application cases. In particular, examples will focus on the quantification of amorphous content during dynamic in-situ X-ray diffraction analyses.
The external intensity standard is used to put all Rietveld quantities on an absolute scale. The use of an external standard phase determines the instrument intensity constant, the so called K-factor. The external standard sample can be any 100% crystalline sample consisting of one or of several phases.
1) B.H. O'Connor & M.D. Raven, Application of the Rietveld Refinement procedure in Assaying Powdered Mixtures, Powder Diffraction (1988), 3, 2-6.

Phase transformation in a Zr-based bulk amorphous alloy during heating has been studied using in situ neutron and synchrotron x-ray diffraction techniques. The transformation kinetics was investigated in conjunction with thermal analysis, which has been analyzed by means of the Johnson-Mehl-Avrami (JMA) method. The metastable phase was identified using the Pair Distribution Function (PDF) method, and its formation can be related to the interdiffusion due to the complex chemical interactions. The analysis method established in the present study provides a new way for probing the kinetics of metastable phase transformation, especially the formation of nanoscale phases, in a broad range of non-crystalline materials.

The development of luminescent ceramic materials has been subject of extensive research in the recent years because of their applications in devices involving the artificial production of light. Particularly, rare earths are widely used as efficient emission centers due the high transition probabilities originating from 4f electron configuration. In this work LnTaO₄ compounds (Ln = rare earth) were synthesized by solid state reaction and the samples were characterized by X-Ray diffraction (XRD), Raman scattering and photoluminescence (PL) emission. The results showed that crystalline materials were obtained with different arrangements according to temperature synthesis and lanthanide ionic radii. PL emission spectra exhibited the typical sharp emission corresponding to transitions from Ln³⁺ ion under UV excitation. It was observed some variation in spectral shape, peak position, and relative intensity as a consequence of the crystal structure. The sample of Tb³⁺ presents a strong green emission with maximum intensity at 549.2 nm and 543.0 nm to M-type and M&’-type arrangements, respectively. This domination emission of Tb³⁺ is related with ⁵D₄→ ⁷F₅ transition. Chromaticity diagrams (CIE) were also determined for the samples LnTaO4, aiming to bring forward the color coordinates for this serie of luminescent ceramic compounds.

Nanocrystalline (NC) and ultrafine grained (UFG) metallic materials have applications as structural materials due to their enhanced strength. Understanding the temperature dependent plastic deformation behaviors of NC and UFG materials is crucial for their high temperature applications. Here we report the diminished ductility of UFG austenitic Fe-14Cr-Ni alloy with temperature increasing from 20 to 200 °C under tension tests [C. Sun, et al. Materials Science and Engineering A, 597 (2014) 415]. By using in situ neutron diffraction technique, we investigated the deformation mechanisms of UFG austenitic Fe-14Cr-16Ni alloy at 20 and 200°C [C. Sun et al., International Journal of Plasticity, 53 (2014) 125]. At 200 °C, non-linear lattice strain deviation on [2 0 0] orientation proceeded plastic yielding by a large margin, accompanied by a greater distortion of crystal structure. In addition, the capability to accumulate dislocations was substantially reduced at 200 °C as evidenced by lower dislocation density than that at 20 °C. Dynamic recovery expedited at elevated temperature because of enlarged critical separation distance for annihilation of dislocation dipoles via climb. Calculations show that both high angle grain boundaries and thermal kinetic energy assisted the reduction of vacancy formation energy. This research is funded by NSF-DMR-Metallic Materials and Nanostructures Program.

Order/disorder processes between, U and Nd, Oxygen and vacancies were studied by X-ray diffraction in U_1-yNd_yO_2-x alloys. It was found, that adjustment of oxygen concentration in U_1-yNd_yO_2-x alloys with different Nd concentration is accompanied by vacancy formation at the Oxygen sublattice. Lattice parameters in the U_1-yNd_yO_2-x alloys deviate from the Vegard&’s law for high concentration of Nd. Lattice parameters and d-spacing consistently decrease with Oxygen concentration at all Nd concentrations indicating the vacancies formation during oxygen adjustment at high temperatures. Change in vacancy concentration after oxygen adjustment is estimated relative to Nd concentration and oxygen stoichiometry. Research is sponsored by the Department of Energy Office of Nuclear Energy, Fuel Cycle Research and Development Program.

We present nanosecond dynamics of structure phase transition in bismuth at high pressures directly measured using picosecond X-ray diffraction with synchrotron radiation and laser-shock compression. It is very important to understand the phase transition dynamics of bismuth in high-pressure science, because the bismuth has multiple phase under 10 GPa and their transition pressure is one of the pressure standard for static compression. We performed nanosecond time-resolved measurements with a laser pump and X-ray probe technique using a plasma-confinement target. The 8-ns pulsed laser was used for generating shock compression, and the 100-ps pulsed X-rays, generated from Photon Factory Advanced Ring at High Energy Accelerator Research Organization Japan, were used for X-ray diffraction. The Debye-Scherrer ring pattern, obtained by a single X-ray pulse, clearly shows diffraction peaks and enables us to determine the crystal structure. The time-resolved X-ray diffraction shows that the Bi-I structure, which is at ambient pressure and temperature, transfers to the Bi-V structure within 5 ns under the compression process. The maximum shock pressure is estimated to be ~11 GPa, which is higher than the reported transition pressure to Bi-V structure (7.7 GPa) by static compression. In this process no trace of other structures, which are stable at lower pressures, has been observed. On the other hand, under the shock-release process, the successive structure change (V-III-II-I structures) takes place along with pressures within 30 ns.

M_n+1AX_n phases (where n = 1-3, M is a transition metal, A is an A-group element and X is nitrogen or carbon) combine properties of both ceramics (refractory, high stiffness, low density, low ductility at room temperature) and metals (high thermal and electric conductivity, thermal shocks resistance, low hardness, mechanical resistance) which makes them attractive for a potentially wide range of applications. MAX phases are however mechanically brittle at low temperatures (T < 800 °C). Generally, it assumes that MAX phases deform by dislocation slip in basal planes, thereby forming pile-ups and walls. The latter may interact to form pairs of low angle tilt boundaries (kink bands) leading to delamination in basal planes. However, these elementary mechanisms and the exact role of microstructural defects are not fully understood yet.
In-situ monotonous and cyclic compression tests coupled with neutron diffraction were performed at room temperature at POLDI-SINQ (Paul Scherrer Institute, Switzerland) on Ti₂AlN polycrystals with lamellar anisotropic microstructure. The diffraction peak evolution (position and profile) with applied stress reveals that lamellar grains parallel to compression axis remain elastic while lamellar grains perpendicular to compression plastify, both families being subjected to strong variations of heterogeneous strains (types II and III). We demonstrate that this behavior originates from the complex response of the very anisotropic lamellar microstructure and explains the reversible hysteric loops exhibited by MAX polycrystals when cycled in the elastic regime [1].
[1] A. Guitton, S. Van Petegem, C. Tromas, A. Joulain, H. Van Swygenhoven and L. Thilly, accepted in Applied Physics Letters

The plastic behavior of micron and submicron sized metallic domains has intensively been studied during the last decade revealing an unexpected size effect of the material strength. To unravel the underlying deformation mechanisms, advanced electron microscopy techniques like transmission electron microscopy (TEM) or scanning electron microscopy (SEM) have extensively been used. TEM investigations are limited to thin, electron transparent samples - typically less than 500nm thick. In situ SEM allows for an excellent alignment of the sample and the counterbody, but is not well able to image single dislocations during multiplication and movement, which both is required for the understanding of the plastic deformation. Advances in focussing X-ray optics during the last decade nowadays allows for white X-ray beams with 200nm full width at half maximum and less. Thus, alternatively, synchrotron based µLaue diffraction offers an complementary view on the damage evolution in micron sized samples.
In the present work in situ µLaue diffraction has been used to investigate the low cycle fatigue behavior of single and bicrystalline Copper and Silver microcantilevers. The µLaue data show an extensive storage of excess dislocations accompanied by the formation of a cellwall-like substructure during bending in one direction. During unloading and backbending, the content of excess dislocations is tremendously reduced leading to an undetectable low content of excess dislocations in the straight bending beam. This has been observed on up to 200 cycles in Copper.
In the talk, the results will be discussed with respect to the availability of dislocation sources at the micron scale, the stacking fault energy of Copper and Silver and the applied accumulated plastic shear strain.

Understanding of the physics under shock compression has been an important subject over the past century. Many experimental results have revealed that the shock-compressed material initially behaves as a purely elastic medium, and finally results in plastic deformation. However, the details of the transition between these two states has not been fully understood. We directly observed transient structural dynamics of iron induced by shock wave using brilliant X-ray Free Electron Laser (XFEL) pulses with a duration less than 10 femtoseconds. We found that the shock at an early stage produces an elastic strain corresponding to a stress of 22 GPa. We suggest that the giant elasticity induces generation of dislocations causing a high density of lattice defects inside the material, and that the plastic deformation without dislocations occurs, which was theoretically predicted but has not been observed. Our findings elucidate mechanisms of ultrafast phenomena under extreme conditions driven by shock compression, and promote to emerge novel characteristics in matters.

The pathways towards a Materials Oscilloscope for studies of metals undergoing physical thermo-mechanical simulation have been laid by the use of monochromatic high-energy synchrotron radiation [Liss-2010]. In this way, reflection morphologies stemming from particular grains were streaked like the trace of an oscilloscope, in-situ and in real time. The so-called azimuthal-angle/time plots allow to observe grain statistics, grain rotation, growth, refinement, subgrain formation and thus distinguish slip, twinning, static and dynamic recovery and recrystallization. In a further development we present here a white beam Laue method, which covers not only one but both dimensions in orientations space. While the Laue method is well employed on single crystals, it usually fails on a polycrystalline or powder material. Here, we make use of a small beam and a small illuminated volume, limiting the number of reflecting grains. As grain growth occurs, reflections from different crystallites separate eventually. Heating fine-grained and highly deformed materials, recrystallization temperatures as well as features during grain growth can be revealed from the data. We have investigated various magnesium and aluminium alloys from which results will be selected for and compared in the presentation.
[Liss-2010] Klaus-Dieter Liss, Kun Yan: “Thermo-mechanical processing in a synchrotron beam”, Materials Science and Engineering: A, 528/1 (2010), p. 11-27. doi 10.1016/j.msea.2010.06.017

The interactions of catalytically functionalized groups with graphene-based electrodes control complex interfacial processes encountered in electrochemical energy conversion systems. However, our knowledge of the atomic/nanoscale reactivity at such functional interfaces remain scarce due to the incomplete understanding of interfacial structures and dynamic processes encountered in operando conditions. In this talk, we will present a systematic study of the solution-based functionalization of epitaxial graphene by the adsorption of a quinone-based molecules, phenanthrenequinone (PQ), combining electrochemical characterization, high-resolution interfacial X-ray scattering and ab-initio density functional theory calculations. Our results reveal that while PQ deposited on pristine graphene is unstable to electrochemical cycling, the prior introduction of defects and oxygen functionality (hydroxyl and epoxide groups) to the graphene basal plane by exposure to an oxygen plasma effectively stabilized its non-covalent functionalization by PQ adsorption. The PQ molecules adsorb by lying down parallel to the basal plane, resembling the graphene layer stacking (as measured in-situ with X-ray reflectivity) and are further stabilized by hydrogen bonding with terminal hydroxyl groups that form at defect sites within the graphene basal plane. PQ retains its expected redox activity associated with the proton coupled electron transfer (PCET) reaction. The resultant PQ adsorption structure is essentially independent of electrochemical potential. These results highlight a novel approach that uses non-covalent interactions to enhance functionalities of the otherwise chemically inert graphene. Such an approach is expected to be widely applicable to many functional adsorbate/2D-crystal systems. The interfacial structures and processes illuminated in this work lay a foundation for understanding relevant interactions between aromatic functional groups with graphene via our in-situ X-ray approach, providing unique insights into the atomistic interactions at fluid-solid interfaces for catalytic energy systems.

The metastable β-type Ti alloys can be obtained through addition of β stabilizing elements such as Nb. In these metastable alloys, the β phase (bcc) is frequently decomposed during the quench into other metastable phases : α" martensite (orthorhombic) or no-sized omega; phase (hexagonal). Thanks to the addition of Zr and Sn elements, the formation of both martensitic α” and omega; phases was restrained in the present as-quenched Ti-24Nb-4Zr-8Sn (wt%, Ti2448 alloy for short) alloy. Thus, the Ti2448 alloy exhibits low Young&’s modulus, high strength and superelasticity which enable it to be a candidate material for bone substitutes (implants or prostheses). However, as a metastable state, the single phase alloy can decompose readily during subsequent thermal treatment. Furthermore, when this alloy is subjected to a deformation, a martensitic phase is prone to appear, therefore called stress induced martensitic α” phase (SIM α”) . In this study, in-situ synchrotron X-ray diffraction (SXRD) at room temperature was performed throughout a whole cyclic tensile test. Based on these SXRD profiles, the cell parameters of orthorhombic α” phase and bcc β phase were calculated in order to reveal the details of this phase transformation. The results show that elastic deformation of the β phase occurs first, followed by the nucleation and the elastic deformation of the α” phase and finally a global plastic deformation happens.