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Neutrons for Science
to the ILL after completing his postdoc at MIT (Boston). A monocrystal selects a monochromatic beam, and the scattered neutrons are measured in a set of detector. A spinning disk (chopper) just before the sample pulses
the beam and allows analysis of the energy of scattered neutrons. The instrument can also use polarised neutrons.
Such were the first instruments foreseen and put into manufacture at the ILL or in European laboratories with existing reactors, (Saclay, Munich, Jülich, Karlsruhe, Grenoble and Risø).
5.1.4 Neutron optics
One aim for all instruments using crystal monochromators, whether for inelastic scattering or diffraction, was to make a large effort to optimise these components. Once again it was
one of Maier-Leibnitz’s ideas to use focussing crystals. This involved the establishment of an infrastructure: furnaces to
grow the crystals, and the means to study their mosaicity. A number of ILL physicists was involved in this research; Andreas Freund was foremost in the field. He joined the ILL at the end
of 1967 to prepare his thesis on this theme with Maier-Leibnitz. He constructed the first X-ray backscattering diffractometer using bremsstrahlung radiation (i.e. white beam), while Jochen Schneider constructed the very first gamma-ray diffractometer78, also in the framework of a thesis. Then Freund gradually became the coordinator of the Monochromator Group in charge of supplying monochromator crystals for the ILL instruments. Three
78 A. Freund and J. Schneider (1972) J. Cryst. Growth, 13/14. 247-251, DOI 10.1016/0022-0248(72)90163-7 105