Reference Material Only

Instrument Calibration

In order to be in a position to make confident statements to the court regarding laboratory X-ray powder diffraction data, you must carefully check the diffractometer before, during, and after any measurements. The following calibration data, based on the NBS 640b silicon standard, was presented as part of the evidence in this particular case study. Note the quality of the fit between observed and calculated positions.

Peak No. hkl 2θ(Obs) (°)
2θ(Calc) (°)
Δ2θ (°)
Intensity
Width (°)
1 111   28.439   28.438 −0.001 558 0.070
2 220   47.300   47.300   0.000 258 0.081
3 311   56.120   56.120   0.000 130 0.091
4 400   69.127   69.129 −0.002   26 0.100
5 331   76.377   76.376   0.001   49 0.101
6 422   88.034   88.032   0.002   56 0.111
7 511   94.954   94.955 −0.001   27 0.125
8 440 106.708 106.714   0.006   18 0.136
9 531 114.100 114.099   0.001   30 0.147
10 620 127.556 127.556   0.000   22 0.186

2θ zero error = −0.007(1)°

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© Copyright 1997-2006.  Birkbeck College, University of London. Author(s): Jeremy Karl Cockcroft
Martin Vickers