Estimation of coherence properties of an undulator-generated x-ray beam from near-field and far-field slit diffraction visibilities

This paper reports on the fabrication and characterization of X-ray waveguide beamsplitters. The waveguide channels were manufactured by electron-beam lithography, reactive ion etching and wafer bonding techniques, with an empty (air) channel forming the guiding layer and silicon the cladding material. A focused synchrotron beam is efficiently coupled into the input channel. The beam is guided and split into two channels with a controlled (and tunable) distance at the exit of the waveguide chip. After free-space propagation and diffraction broadening, the two beams interfere and form a double-slit interference pattern in the far-field. From the recorded far-field, the near-field was reconstructed by a phase retrieval algorithm (error reduction), which was found to be extremely reliable for the two-channel setting. By numerical propagation methods, the reconstructed field was then propagated along the optical axis, to investigate the formation of the interference pattern from the two overlapping beams. Interestingly, phase vortices were observed and analysed.

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Two-dimensional Near-field and Far-field Imaging of a Ne-like Ar Capillary Discharge Table-top Soft X-ray Laser

Optics and Photonics News ◽

10.1364/opn.9.12.000055 ◽

1998 ◽

Vol 9 (12) ◽

pp. 55

Author(s):

C. H. Moreno ◽

M. C. Marconi ◽

V. N. Shlyaptsev ◽

B. R. Benware ◽

C. D. Macchietto ◽

...

Keyword(s):

Near Field ◽

Capillary Discharge ◽

Far Field ◽

Two Dimensional ◽

X Ray ◽

Field Imaging

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An algorithm for resolving intragranular orientation fields using coupled far-field and near-field high energy X-ray diffraction microscopy

Materials Characterization ◽

10.1016/j.matchar.2020.110366 ◽

2020 ◽

Vol 165 ◽

pp. 110366 ◽

Cited By ~ 5

Author(s):

Kelly E. Nygren ◽

Darren C. Pagan ◽

Joel V. Bernier ◽

Matthew P. Miller

Keyword(s):

Near Field ◽

High Energy ◽

Far Field ◽

X Ray Diffraction ◽

X Ray ◽

Orientation Fields ◽

Diffraction Microscopy

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Two-dimensional near-field and far-field imaging of a Ne-like Ar capillary discharge table-top soft-x-ray laser

Physical Review A ◽

10.1103/physreva.58.1509 ◽

1998 ◽

Vol 58 (2) ◽

pp. 1509-1514 ◽

Cited By ~ 31

Author(s):

C. H. Moreno ◽

M. C. Marconi ◽

V. N. Shlyaptsev ◽

B. R. Benware ◽

C. D. Macchietto ◽

...

Keyword(s):

Near Field ◽

Capillary Discharge ◽

Far Field ◽

Two Dimensional ◽

X Ray ◽

Field Imaging

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Comparison between a near-field and a far-field indexing approach for characterization of a polycrystalline sample volume containing more than 1500 grains

Journal of Applied Crystallography ◽

10.1107/s160057671401406x ◽

2014 ◽

Vol 47 (4) ◽

pp. 1402-1416 ◽

Cited By ~ 11

Author(s):

Laura Nervo ◽

Andrew King ◽

Jonathan P. Wright ◽

Wolfgang Ludwig ◽

Péter Reischig ◽

...

Keyword(s):

Diffraction Data ◽

Near Field ◽

Three Dimensional ◽

Pure Titanium ◽

Polycrystalline Sample ◽

Sample Volume ◽

Polycrystalline Materials ◽

Far Field ◽

X Ray Diffraction ◽

X Ray

A comparison of the performance of X-ray diffraction tomography, a near-field diffraction technique, and a far-field diffraction technique for indexing X-ray diffraction data of polycrystalline materials has been carried out by acquiring two sets of diffraction data from the same polycrystalline sample volume. Both approaches used in this study are variants of the three-dimensional X-ray diffraction (3DXRD) methodology, but they rely on different data-collection and analysis strategies. Previous attempts to assess the quality of 3DXRD indexing results from polycrystalline materials have been restricted to comparisons with two-dimensional electron backscatter diffraction cross sections containing a limited number of grains. In the current work, the relative performance of two frequently used polycrystalline-material indexing algorithms is assessed, comparing the indexing results obtained from a three-dimensional sample volume containing more than 1500 grains. The currently achievable accuracy of three-dimensional grain maps produced with these algorithms has been assessed using a statistical analysis of the measurement of the size, position and orientation of the grains in the sample. The material used for this comparison was a polycrystalline commercially pure titanium grade 2 sample, which has a hexagonal close-packed crystal structure. The comparison of the two techniques shows good agreement for the measurements of the grain position, size and orientation. Cross-validation between the indexing results shows that about 99% of the sample volume has been indexed correctly by either of these indexing approaches. The remaining discrepancies have been analysed and the strengths and limitations of both approaches are discussed.

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Visualizing Near-Field Spray Characteristics With Broadband X-Rays

Volume 1B, Symposia: Fluid Measurement and Instrumentation; Fluid Dynamics of Wind Energy; Renewable and Sustainable Energy Conversion; Energy and Process Engineering; Microfluidics and Nanofluidics; Development and Applications in Computational Fluid Dynamics; DNS/LES and Hybrid RANS/LES Methods ◽

10.1115/fedsm2017-69088 ◽

2017 ◽

Author(s):

Danyu Li ◽

Timothy B. Morgan ◽

Luke D. Pulfer ◽

Theodore J. Heindel

Keyword(s):

Laser Diagnostics ◽

Near Field ◽

Far Field ◽

X Rays ◽

Spray Nozzle ◽

Field Region ◽

Spray Characteristics ◽

X Ray ◽

Sheet Breakup ◽

Optical Laser

Liquid sprays play a key role in many engineering processes (e.g., food processing, coating and painting, 3D printing, fire suppression, agricultural production, combustion systems, etc.). Spray characteristics can easily be assessed in the mid- and far-field regions, well after liquid sheet breakup and droplet formation, using various optical/laser diagnostic techniques. The conditions in the near-field region, near the spray nozzle exit, can influence mid- and far-field characteristics; however, near-field measurements are extremely challenging because the spray in this region is typically optically dense and optical/laser diagnostics are ineffective in this region. This study presents the advantages and challenges of using broadband X-rays to characterize the near-field region of a spray. A generic spiral jet hollow cone spray nozzle is used to demonstrate near-field spray imaging for three different flow conditions. Radiographic movies of the spray show a very dynamic near-field region. X-ray computed tomography (CT) reconstructions of the spray display a 3D map of the time-average spray distribution. The two X-ray imaging modes provide qualitative information of the near-field spray region. A discussion of the quantitative measures that can be acquired from X-ray radiographs and CT images is provided.

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