CONSIDERATION OF SEVERAL FACTORS IN THE METHOD FOR MAPPING X-RAY ROCKING CURVES

The resolution and dispersion arising from the diffraction geometry us ed in the method developed by Gao et al. for mapping x-ray rocking cur ves are discussed in detail. The effects of the resolution of the one- dimensional detector on the measurement of rocking curves and on the m easurement of rocking curve contour maps have also been investigated. The dispersive effect (i.e., Delta lambda/lambda) in the diffraction g eometry is reduced by an order of magnitude and is negligible compared with the intrinsic angular width of the crystal for a wide range of s ample crystal Bragg angles (say the range varies from 10 degrees to 60 degrees, using Cu K alpha(1) radiation), provided that the resolution of the detector is better than 0.2 mm. This means that the dispersive effect of nearly all crystal samples will be negligible if rocking cu rves are measured using the present method and Cu K alpha(1) radiation . The results also apparently show that the full width at half maximum of the rocking curves increases and the resolution of contour maps de creases when the resolution of the detector is poorer than 0.2 mm. (C) 1995 American Institute of Physics.