scholarly journals GALAXI: Gallium anode low-angle x-ray instrument

2016 ◽  
Vol 2 ◽  
Author(s):  
Emmanuel Kentzinger ◽  
Margarita Krutyeva ◽  
Ulrich Rücker
Keyword(s):  
Synchrotron Radiation ◽  
Small Angle ◽  
Radiation Source ◽  
Second Generation ◽  
Grazing Incidence ◽  
Bulk Materials ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Geometry ◽  
The One

The high brilliance laboratory small angle X-ray scattering instrument GALAXI, which is operated by JCNS, Forschungszentrum Jülich, permits the investigation of chemical correlations in bulk materials or of structures deposited on a surface at nanometre and mesoscopic length scales. The instrument is capable to perform GISAXS experiments in reflection at grazing incidence as well as SAXS experiments in transmission geometry. The X-ray flux on sample is comparable or higher than the one obtained at a comparable beamline at a second generation synchrotron radiation source. 

Effect of filtration forces on the structure of casein micelles

2013 ◽  
Vol 47 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Ronald Gebhardt
Keyword(s):  
Small Angle ◽  
Membrane Filtration ◽  
Grazing Incidence ◽  
Filtration Flow ◽  
Casein Micelles ◽  
X Ray ◽  
X Ray Scattering ◽  
The One ◽  
Prolate Ellipsoidal ◽  
Ray Scattering

Pressure-driven membrane filtration is a widely used method to separate casein micelles (CM) from smaller components in milk. The structure of CM attached on the membrane has been investigated because in such a deposited state they reduce the performance of the filtration process. Scattering experiments with nano- and micrometre sized X-ray beams and a filtration setup with silicon micro-sieves as membranes were used. Grazing-incidence small-angle X-ray scattering (GISAXS) experiments above porous regions of the micro-sieves show that spherical CM become stretched in the direction of the filtration flow. The one-dimensional scattering functions extracted from the two-dimensional GISAXS patterns were analyzed by a single ellipsoidal form factor fit. According to the model, CM assume a prolate ellipsoidal shape at a trans-membrane pressure of Δp= 400 mbar (1 mbar = 100 Pa). With increasing trans-membrane pressure, the shape of the CM undergoes a transition towards an oblate structure between 400 and 600 mbar. Small-angle X-ray scattering experiments with a 200 nm beam allow for transmission experiments on CM in a single pore of the micro-sieve. Typical characteristics of the internal structure could not be identified in the scattering functions of CM subjected to filtration forces.

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