Figure 15
(a) The intensity measured in the vicinity of the 220 Bragg peak from a crystallite by isolating it from a larger diffraction space map, measured by Patricia Kidd. The geometry used was the Beam-Selection-Diffractometer (Fewster, 2004), with a 100 µm double pinhole, Cu Kα and 220 Ge analyser crystal. The near-perfect match of the reflection choices removes the wavelength dispersion to reveal the intrinsic width of the Bragg peak, which is 0.002°. Along Ω is blurred by diffuse scattering and the pinhole geometry. This can be compared with Fig. 7, although this extremely high resolution diffraction space map is truncated because of the limited acceptable axial divergence. The maximum intensity is ∼2 counts s−1. (b) is the projected sum of the central region of the map. |