Neutron Scattering

Fig. 18.14: Variation of reflection
intensities ivith rp rotation (x
f'xed) ofa quartzit sample
measured ivith a large linear
detector in Jülich
Rather than using a single counfng tube it is more efficient to employ a large positionsensitive
detector which covers a wide scattering range 20 and which allows the simultaneous
measurement of many (hkl) reflections (see Fig . 18 .14) and, finis, the collection of
experimental data for many pole figures in only one sample scan . The pole figures are
constructed (1) by conversion of the individual sample orientations (cp, x) into pole figure
coordinates (a, ß), (2) by interpolation for points of an almost equispaced (a, ß)-grid in the
pole figure projection (sec Fig . 18 .13) and (3) by graphically representing the pole figures
with the corresponding reflection intensifies (compare Fig . 18 .15) .
Fig . 18.15 : Comparison of c-axis polefigures (0001) ofa texturized quartzite obtainedfrom
single grain analysis by U-stage inicroscopy (left) and neutron diffraction (right) based on
investigations ofabout one hundred and one million grains, respectively .
4.3 Pole Figures from Neutrons and X-Rays
The advantages and drawbacks of both neutron and X-ray diffraction for texture analysis are
obvions . Texture is a statistical description of ciystallite orientations and therefore requires a
large number of ciystallites or grains in order to get a meaningful sampling . Reproducible
18- 9