The X-ray Colour Camera Microscope: A white beam instrument for combined single-shot X-ray diffraction, fluorescence, and absorption measurements

QUICK INFORMATION
Type
Seminar
Start Date
16-01-2020 09:00
End Date
16-01-2020 10:00
Location
Room 500 - 501, Central Building
Speaker's name
Phil K. Cook
Speaker's institute
University of Natural Resources and Life Sciences, Institute for Physics and Materials Science, Vienna, Austria
Contact name
Eva Jahn
Host name
Veijo Honkimaki
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In many composite materials, both engineered and natural, the final properties and desired characteristics are determined by the microstructure, of which the 3-dimensional crystal texture is a key component. As such, the determination of crystallographic texture and understanding its impact on material properties is of great interest in materials science. Using current techniques based on 2D X-ray detectors, determination of 3D crystal texture requires tilting or rotating the sample. In order to map the texture across, for example, a piece of carbon fibre reinforced composite, this tilt must be performed at each point, leading to long acquisition times. The need to tilt samples also places constraints on possible in situ experiments.
In response to the need for faster 3D texture measurements, we are developing the X-ray Colour Camera Microscope (XCCM). The XCCM is based around a 1-megapixel pnCCD detector [1] which provides direct detection of X-rays with both energy and spatial resolution. The detector reaches an energy resolution of 130 eV, comparable to standard silicon drift detectors, with a pixel size of 75 x 75 μm2. An Excillum Liquid Metal Jet X-ray source provides an X-ray Bremsstrahlung spectrum up to 70 keV with peaks at the gallium and indium K-lines. A monocapillary optic focuses the white beam to a ~20 μm spot on the sample. An additional optic tool will allow insertion of apertures before or after the sample to tune the spot size or permit full-field X-ray fluorescence imaging. By closely approaching the detector to the sample, we can reach scattering angles up to 70°.
Illuminating a sample using the white beam will yield a data cube of (x, y, energy) produced by the detector, which can be transformed into a pole figure [2] or interpreted directly. In addition to collecting diffraction data within a segment of reciprocal space, the detector will simultaneously record the X-ray fluorescence of the sample and the attenuation of the incident beam by the sample. In addition to the lab-based configuration, the detector has been designed to be portable in order to perform experiments at synchrotrons. Proof-of-concept experiments have already been carried out at ESRF BM28 using a similar detector [2].
1. Lothar Strüder, et al. (2010) Large-format, high-speed, X-ray pnCCDs combined with electron and ion imaging spectrometers in a multipurpose chamber for experiments at 4th generation light sources, Nucl. Instrum. Methods Phys. Res. Sect. A, 214, 483 – 496.
2. T.A. Grünewald, et al. (2016) Photon energy becomes the 3rd dimension in crystallographic texture analysis, Angewandte Chemie Int. Ed., 55 (40), 12190–12194.

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