Customer: ILL. Institut Laue Langevin (Grenoble. France)
The ROC is a device placed in the scattered neutron beam between the sample and the detector. It consists on an array of absorbent blades periodically spaced, which constrain the angular view of each point at the surface of detection. The blades are made of a polymeric material (PETP) coated with several layers of a neutron absorbent substance (e.g. Gd-Oxide). All those blades are under vertical stress, the aim of this is to maintain them straight and parallel among them. These blades are hold in a stiff frame screwed on a plate (trolley). The frame made of non magnetic alloy (aluminium alloy) is surrounding the blades on the sides and on the top and bottom. No pillar or stiffener is admitted in the path of the neutron beam.
Moreover, those blades have to swing over certain angular amplitude D2q which has to be a multiple of the periodicity of the ROC. The velocity of the swing must be constant and reproducible.