Neutron-diffraction experiments geometry

At the time the neutron diffraction experiments were carried out it was not known that there are two forms of amorphous solid water. Consequently, although the deposition system was designed to ensure elimination of crystalline ice in the sample, neither the geometry nor the deposition rate were the same as used in the X-ray experiments of Narten, Venkatesh and Rice 7>27>. We shall argue below that although the substrate temperature used by WLR was low, their data are only consistent with diffraction from high temperature low density D20(as). 

The geometry of a neutron diffraction experiment is shown in Fig. 3.2, where a neutron of incident wavevector ki is scattered into a state with wavevector kf. In the case of nnclear scattering, the scattering centre is the atontic nucleus. The essential information that is determined in a nentron (or X-ray) diffraction measurement is the differential scattering cross-section ... 

Fig. 5.6. Geometry of a diffraction or scattering experiment (for X-rays, neutrons or light)...

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