Terms of reference
The Commission on Neutron Diffraction was established at the Moscow General Assembly in 1966. The proposal at that time is given below.
The Commission on Neutron Diffraction shall be concerned with those aspects of crystallography which can be studied almost uniquely by using neutron beams. Broadly these fall into three classes:
- Satisfactory detection of light atoms (particularly hydrogen)
- The detection and description of magnetic architecture
- The study of crystal dynamics from inelastic scattering data
It is considered that there are several ways in which these aims can be directly advanced and that there is a substantial need for action at the present time in these various directions.
- Tabulation and critical evaluation of data on the neutron scattering amplitudes of elements and isotopes, including complex scattering amplitudes, and of magnetic form factors. There are wide variations of accuracy among the accepted values and the accuracies of many of them are not known.
- Collection of information and recommendations on technical procedures, e.g. choice of initial collimation, the uses of Soller slits, choice and availability of monochromators, corrections for secondary extinction, multiple scattering and series termination.
- Cataloguing of information on reactor types, neutron flux, background, instrumentation, methods of data collection and handling, design of cryostats and magnet assemblies.
- Encouragement of monographs, e.g. on Shubnikov groups, and their application to the determination of magnetic structures, inelastic scattering techniques. Cooperation in the production of Structure Reports for the description of magnetic structures.
- Support for symposia, in particular to ensure that the various aspects of neutron diffraction techniques, such as those mentioned above, get adequate coverage in meetings of the International Union of Crystallography. This need is quite distinct from providing coverage of the results of neutron-diffraction investigations.
At the Beijing General Assembly in 1993, the name of the Commission was changed to the slightly more general Commission on Neutron Scattering
. This change was made because the Commission wished to represent and serve all neutron scatterers who consider that they use crystallographic techniques.
Updated 25 September 1997
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