Variable knife edge features

The MiniFlex300/600 can be equipped with the D/teX Ultra high-speed 1-dimensional detector to obtain greater intensity. This detector has a broad detection surface and can efficiently count diffraction X-rays from a sample. As a result, it is possible to obtain intensities from a few tens to roughly 100 times greater than a scintillation counter. Background can also be reduced using the fluorescent X-ray reduction mode, or knife edge etc. Fig. 1 shows the X-ray diffraction patterns obtained when a knife edge is installed versus no knife edge. By using a knife edge, it is possible to achieve an extreme reduction in scattering on the low-angle side. Also, the knife edge moves in a way which is dependent on the diffraction angle 2θ, and thus there is no blind spot (intensity attenuation) on the high-angle side, and measurement can be done from the low-angle side to the high-angle side.

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Fig. 1: X-ray diffraction patterns (enlarged) of zeolite,
measured when a knife edge is installed
versus no knife edge.

Fig. 2 shows the X-ray diffraction patterns for milk chocolate and bitter chocolate, measured using a knife edge. The background on the low-angle side is suppressed to a low level, and it is evident that the diffraction peaks on the low-angle side of the cacao butter (POS: a structure combining palmitic acid, oleic acid and stearic acid) contained in the chocolate are clearly observed. Without using a knife edge it would have been harder to observe the low angle peaks, especially for the minor component.

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Fig. 2: Qualitative analysis results for milk chocolate and bitter chocolate

Apparatus condition:

MiniFlex600 (F.F tube 40 kV, 15mA), Detector: D/teX Ultra, Slit conditions: DS = 0.625°, SS = 8 mm, RS = 13mm, Incident side and receiving side Soller slit: 5°, Incident height limiting slit = 10 mm

Measurement condition:

Scan range: 2θ = 3 ~ 40°, Step width: 0.02°, Scan speed: 20° / min. (about 2 min.)


MiniFlexNew sixth generation MiniFlex X-ray diffractometer (XRD) is a multipurpose analytical instrument that can determine: phase identification and quantification, percent (%) crystallinity, crystallite size and strain, lattice parameter refinement, Rietveld refinement, and molecular structure. It is widely used in research, especially in material science and chemistry, as well as in industry for research and quality control. It is the newest addition to MiniFlex series of benchtop X-ray diffraction analyzers from Rigaku, which began with the introduction of the original MiniFlex system decades ago. Read more about Rigaku's MiniFlex...

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