486 research outputs found
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No full textTestdatensatz
zu Abbildung 7a in M. Osterhoff et al: Nanosecond timing and synchronization scheme for holographic pump–probe studies at the MID instrument at European XFEL, https://doi.org/10.1107/S160057752100305
Coherence Filtering of X-Ray Waveguides: Analytical and Numerical Approach
No full textWe model and describe the spatial coherence and mutual intensity of focused synchrotron radiation x-ray beams, based on ensemble averagesof stochastic superpositions. Within this framework, we present numerical calculations for typical synchrotron sources with focusing mirrors, and simulate the evolution of coherence inside x-ray waveguides used for filtering by analytical and numerical methods. Simulated focus fields are compared with an experimental setup, including figure errors and vibrations
HiPACE++ input scripts for "Self-stabilizing positron acceleration in a plasma column"
No full textThis dataset presents the HiPACE++ input scripts required to re-create the data of Fig. 2 and 4 in the article "Self-stabilizing positron acceleration in a plasma column" by S. Diederichs, C. Benedetti, M. Thévenet, E. Esarey, J. Osterhoff, and C. B. Schroeder
In-line holography with hard x-rays at sub-15 nm resolution
No full textX-ray in-line holography is well suited for three-dimensional imaging, since it covers a large field of view without the necessity of scanning. However, its resolution does not extend to the range covered by coherent diffractive imaging or ptychography. In this work, we show full-field holographic x-ray imaging based on cone-beam illumination, beyond the resolution limit given by the cone-beam numerical aperture. Image information encoded in far-field diffraction and in holographic self-interference is treated in a common reconstruction scheme, without the usual empty beam correction step of in-line holography. An illumination profile tailored by waveguide optics and exactly known by prior probe retrieval is shown to be sufficient for solving the phase problem. The approach paves the way toward high-resolution and dose-efficient x-ray tomography, well suited for the current upgrades of synchrotron radiation sources to diffraction-limited storage rings
Erratum: X-Ray Optics on a Chip: Guiding X Rays in Curved Channels [Phys. Rev. Lett. <b>115</b> , 203902 (2015)]
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X-ray waveguide arrays: tailored near fields by multi-beam interference
No full textA novel 1‐D X‐ray waveguide, the Mo/C waveguide array (WGA), is introduced to tailor the optical near field distribution by precisely designed and controlled multi‐beam interference at 19.9 keV hard X‐ray energy. Seven precisely controlled guiding layers with optimized layer thickness variation were fabricated by high‐precision direct‐current magnetron sputtering of amorphous carbon (C) and molybdenum (Mo). The thickness variations are designed in such a way to introduce the desired phase shifts between the guided output beams, to act as a quasi‐focusing device. The WGA and the layer thicknesses are characterized by X‐ray reflectivity, transmission electron microscopy, and measurement of the synchrotron radiation far‐field intensity pattern. Based on the measurements and simulations, a reliable Mo/C multilayer layers combination can be verified. With the layers thicknesses, simulations inside the WGA and in the optical near field behind it show that multi‐beam interference with the designed phase shifts lead to a relative beam intensity of 0.59 in a quasi‐focal plane 0.08 mm behind the exit, with a spot size of 23.8 nm
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