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The one-dimensional (1-D) X-ray beam diffuser was developed to reduce horizontal stripe-shaped intensity irregularities on the beam from a multilayer monochromator while keeping the horizontal spatial coherence of the beam required for phase measurements using a grating interferometer. The diffused beam showed a smoothed beam profile without degrading the visibility of Moiré fringes in the grating interferometer. In the X-ray phase tomographic measurement, a sectional image with the beam diffuser showed clear structure without artifacts while the sectional image without the diffuser suffered from the remaining striped-shaped artifacts.

Full-field transmission X-ray microscopy (TXM) is a very potent high-resolution X-ray imaging technique. However, it is challenging to achieve fast acquisitions because of the limited efficiency of the optics. Using a broader energy bandwidth, for example using a multilayer monochromator, directly increases the flux in the experiment. The advantage of more counts needs to be weighed against a deterioration in achievable resolution because focusing optics show chromatic aberrations. This study presents theoretical considerations of how much the resolution is affected by an increase in bandwidth as well as measurements at different energy bandwidths (ΔE/E = 0.013%, 0.27%, 0.63%) and the impact on achievable resolution. It is shown that using a multilayer monochromator instead of a classical silicon double-crystal monochromator can increase the flux by an order of magnitude with only a limited effect on the resolution.

Full‐field transmission X‐ray microscopy (TXM) is a very potent high‐resolution X‐ray imaging technique. However, it is challenging to achieve fast acquisitions because of the limited efficiency of the optics. Using a broader energy bandwidth, for example using a multilayer monochromator, directly increases the flux in the experiment. The advantage of more counts needs to be weighed against a deterioration in achievable resolution because focusing optics show chromatic aberrations. This study presents theoretical considerations of how much the resolution is affected by an increase in bandwidth as well as measurements at different energy bandwidths (ΔE/E = 0.013%, 0.27%, 0.63%) and the impact on achievable resolution. It is shown that using a multilayer monochromator instead of a classical silicon double‐crystal monochromator can increase the flux by an order of magnitude with only a limited effect on the resolution. [ABSTRACT FROM AUTHOR]

Finite‐element analysis is used to study the thermal deformation of a multilayer mirror due to the heat load from the undulator beam at a low‐emittance synchrotron source, specifically the ESRF‐EBS upgrade beamline EBSL‐2. The energy bandwidth of the double‐multilayer monochromator is larger than that of the relevant undulator harmonic, such that a considerable portion of the heat load is reflected. Consequently, the absorbed power is non‐uniformly distributed on the surface. The geometry of the multilayer substrate is optimized to minimize thermally induced slope errors. We distinguish between thermal bending with constant curvature that leads to astigmatic focusing or defocusing and residual slope errors. For the EBSL‐2 system with grazing angles gθ between 0.2 and 0.4°, meridional and sagittal focal lengths down to 100 m and 2000 m, respectively, are found. Whereas the thermal bending can be tuned by varying the depth of the 'smart cut', it is found that the geometry has little effect on the residual slope errors. In both planes they are 0.1–0.25 µrad. In the sagittal direction, however, the effect on the beam is drastically reduced by the 'foregiveness factor', sin(gθ). Optimization without considering the reflected heat load yields an incorrect depth of the 'smart cut'. The resulting meridional curvature in turn leads to parasitic focal lengths of the order of 100 m. [ABSTRACT FROM AUTHOR]

Protein dynamics contribute to protein function on different time scales. Ultrafast X‐ray diffraction snapshots can visualize the location and amplitude of atom displacements after perturbation. Since amplitudes of ultrafast motions are small, high‐quality X‐ray diffraction data is necessary for detection. Diffraction from bovine trypsin crystals using single femtosecond X‐ray pulses was recorded at FemtoMAX, which is a versatile beamline of the MAX IV synchrotron. The time‐over‐threshold detection made it possible that single photons are distinguishable even under short‐pulse low‐repetition‐rate conditions. The diffraction data quality from FemtoMAX beamline enables atomic resolution investigation of protein structures. This evaluation is based on the shape of the Wilson plot, cumulative intensity distribution compared with theoretical distribution, I/σ, Rmerge/Rmeas and CC1/2 statistics versus resolution. The FemtoMAX beamline provides an interesting alternative to X‐ray free‐electron lasers when studying reversible processes in protein crystals. [ABSTRACT FROM AUTHOR]

Multilayer monochromator devices are commonly used at (imaging) beamlines of synchrotron facilities to shape the X‐ray beam to relatively small bandwidth and high intensity. However, stripe artefacts are often observed and can deteriorate the image quality. Although the intensity distribution of these artefacts has been described in the literature, their spectral distribution is currently unknown. To assess the spatio‐spectral properties of the monochromated X‐ray beam, the direct beam has been measured for the first time using a hyperspectral X‐ray detector. The results show a large number of spectral features with different spatial distributions for a [Ru, B4C] strip monochromator, associated primarily with the higher‐order harmonics of the undulator and monochromator. It is found that their relative contributions are sufficiently low to avoid an influence on the imaging data. The [V, B4C] strip suppresses these high‐order harmonics even more than the former, yet at the cost of reduced efficiency. [ABSTRACT FROM AUTHOR]

In recent years, X-ray radiography has been used to probe the internal structure of dense sprays with microsecond time resolution and a spatial resolution of 15 µm even in high-pressure environments. Recently, the 7BM beamline at the Advanced Photon Source (APS) has been commissioned to focus on the needs of X-ray spray radiography measurements. The spatial resolution and X-ray intensity at this beamline represent a significant improvement over previous time-resolved X-ray radiography measurements at the APS. [ABSTRACT FROM AUTHOR]

Abstract: Nickel/titanium multilayers (ML) and supermirrors (SM) were fabricated by DC magnetron sputtering on glass or Si (100) substrates. It was possible to increase the reflectivity of ML and SM by the deposition of an ultrathin Cr layer at the Ni/Ti interfaces. Interdiffusion decreases when the Ni and Ti are separated by a covering Cr layer (3Å), whereas, in the range where the Cr interlayer thickness is higher than the Ni/Ti interdiffusion depth (approximately 6Å) or the surface roughness, the growth of a closed Cr layer is prohibited reducing the reflectivity. The presence of a 10Å Cr interlayer on some Ti layers also results in enhanced reflectivities due to a smoothing effect of the interface for the following layers. The reflectivities of two monochromators for and a bandwidth (Δλ/λ) of 6% and 12% reach a value of approximately 0.90. [Copyright &y& Elsevier]

• The in-situ low-temperature and high-temperature treatments were performed. • W/Si multilayers have superior structural stability and a weak contraction. • Ru/C and Ni/Ti multilayers relates to a mounded interface and others satisfies the KPZ model. • Multilayers have no obvious change in roughness but a decrease in fractal exponent. • After heating 400 °C, Ru/C and Ni/Ti multilayers experience significant structural changes. With the extensive demands of high-flux beamlines for current or planned synchrotron radiation sources, it is important to use multilayer monochromators for beamlines with insertion devices to select required quasi-monochromatic beams. Few studies have reported the interface evolution of multilayer monochromators in the liquid nitrogen (LN 2) cooling environment under intense white beam irradiation. In this research, an in situ grazing-incidence small-angle X-ray scattering (GISAXS) setup was designed to monitor different interface characteristics of Ru/C, Cr/C, W/Si, and Ni/Ti multilayers from the LN 2 temperature to 600 °C. The temperature treatment was executed in three steps — (i) the long-term low-temperature treatment, (ii) the quick temperature variation treatments, and (iii) the high-temperature treatment. A surface profiler was also used to determine the lower-frequency surface roughness after different temperature treatments. The temperature-dependent performances of multilayers were analyzed along the layer deposition direction and the out-of-plane direction. Scattering along the deposition direction reveals different interface features of the multilayers based on their thermal expansions. The power spectral density curve fitting proves that the fractal exponent is very sensitive to temperature change. Most of multilayers have a lower fractal exponent at the LN 2 temperature. Moreover, clear interfacial changes were observed in Ru/C and Ni/Ti multilayers during high-temperature treatments. [ABSTRACT FROM AUTHOR]