Blar i Publikasjoner fra CRIStin - NTNU på forfatter "Falch, Ken Vidar"
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Analytical transmission cross-coefficients for pink beam X-ray microscopy based on compound refractive lenses
Falch, Ken Vidar; Detlefs, Carsten; Snigirev, Anatoly; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2018)Analytical expressions for the transmission cross-coefficients for x-ray microscopes based on compound refractive lenses are derived based on Gaussian approximations of the source shape and energy spectrum. The effects of ... -
Correcting lateral chromatic aberrations in non-monochromatic X-ray microscopy
Falch, Ken Vidar; Detlefs, Carsten; Di Michiel, Marco; Snigireva, Irina; Snigirev, Anatoly; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2016)Lateral chromatic aberration in microscopy based on refractive optics may be reduced significantly by adjustments to the illumination scheme. By taking advantage of a broadened bandwidth illumination, the proposed scheme ... -
Experimental investigation of Gaussian random phase screen model for x-ray diffusers
Falch, Ken Vidar; Detlefs, Carsten; Christensen, Magnus Sebastian; Paganin, David; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2019)The beam diffusing properties of stacked layers of diffuser material were evaluated experimentally and compared to a Gaussian random phase screen model. The model was found to give promising accuracy in combination with a ... -
In situ hard X-ray transmission microscopy for material science
Falch, Ken Vidar; Casari, Daniele; Di Michiel, Marco; Detlefs, Carsten; Snigirev, Anatoly; Snigireva, Irina; Honkimäki, Veijo; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2017)Hard X-ray transmission microscopy based on refractive X-ray optics can be employed as a tool in material science to investigate buried-in microstructures in two or three dimensions with spatial resolution approaching 100 ... -
Non-steady 3D dendrite tip growth under diffusive and weakly convective conditions.
Mirihanage, Wajira; Falch, Ken Vidar; Casari, Daniele; McFadden, Shaun; Browne, David J.; Snigireva, I.; Snigirev, Anatoly; Li, Yanjun; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2019)Three dimensional α-Al dendrite tip growth under varying solute gradients in an Al-Cu-Si alloy melt has been studied using real time synchrotron X-ray imaging and mathematical modelling. X-radiographic image sequences with ... -
Retrieval of three-dimensional spatial information from fast in situ two-dimensional synchrotron radiography of solidification microstructure evolution
Mirihanage, Wajira; Falch, Ken Vidar; Snigireva, Irina; Snigirev, A; Li, Yanjun; Arnberg, Lars; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2014)In situ synchrotron X-ray radiography of columnar dendritic growth in Al–15 wt.% Cu–9 wt.% Si–0.015 wt.% Sr alloy has been carried out with the temporal and spatial resolutions of 100 ms and 0.65 μm, respectively. ... -
Zernike phase contrast in high-energy x-ray transmission microscopy based on refractive optics
Falch, Ken Vidar; Lyubormiskiy, Mikhail; Casari, Daniele; Snigirev, Anatoly; Snigireva, Irina; Detlefs, Carsten; Di Michiel, Marco; Lyatun, Ivan; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2018)The current work represents the first implementation of Zernike phase contrast for compound refractive lens based x-ray microscopy, and also the first successful Zernike phase contrast experiment at photon energies above ... -
α-Mg primary phase formation and dendritic morphology transition in solidification of a Mg-Nd-Gd-Zn-Zr casting alloy
Casari, Daniele; Mirihanage, Wajira; Falch, Ken Vidar; Ringdalen, Inga Gudem; Friis, Jesper; Schmid-Fetzer, Rainer; Zhao, Dongdong; Li, Yanjun; Sillekens, Wim H.; Mathiesen, Ragnvald (Journal article; Peer reviewed, 2016)Microstructure evolution in the commercial Mg-Nd-Gd-Zn-Zr alloy Elektron 21, solidified under nearly isothermal conditions, has been studied via in-situ X-ray radiography. For cooling rates View the MathML source≤0.075 ...