Differences in intensity/resolution due to differences in X-ray tubes

With the MiniFlex300/600, it is possible to select a fine focus tube (focal point size 0.4 x 8 mm²) in addition to a normal focus tube (focal point size 1 x 10 mm²) of the type generally used with powder X-ray diffractometers. Fig. 1 shows an overlay of diffraction peaks obtained by measuring with a normal focus tube and fine focus tube. Table 1 shows a comparison of intensity, and full width at half maximum (FWHM), which varies proportionally with resolution.

Table 1: Intensity ratios and full width at half maximum due to differences in focal point size
Fig. 1: Comparison of normal focus tube and fine focus tube

Both intensity and resolution can be improved by using a fine focus tube. Therefore, these tubes are suitable for measuring samples with many peaks, and samples containing trace components. Fig. 2 shows qualitative analysis results, and quantitative analysis results using the Rietveld method, for a cement sample (NIST 2686 standard material). In the analysis results, there was a good match, within the error range, between the content of each crystal phase, and the standard values for NIST 2686 standard material.

Fig. 2: Qualitative and quantitative analysis results for cement sample (NIST 2686 standard material)
Apparatus and Measurement conditions

Apparatus conditions:

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

Measurement conditions:

Scan range: 2θ = 5 ~ 90°, Step width: 0.02°, Scan speed: 5° / min. (about 18 min.)

New 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...

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