IMAT – the new neutron Imaging and diffraction beamline at ISIS

Orateur : Genoveva BURCA (ISIS - Didcot - United Kingdom)

IMAT is a thermal and cold neutron facility designed for imaging and diffraction applications being built on the ISIS second target station (TS-2) at the Rutherford Appleton Laboratory, UK. IMAT will combine imaging and diffraction techniques on one beamline, a possibility which is not currently available at any other single instrument. The combination of diffraction and imaging on one beamline would enable more advanced studies on materials than if separate beamlines were to be used. By taking advantage of the Bragg edges in the energy-dependant neutron cross-section and by exploiting the capability of a pulsed source to select optimal energies, materials which are not visible with the standard neutron radiography can be made visible or transparent. Hence, while microstructure properties (e.g. crystallographic texture) can be mapped with high resolution in transmission mode, the diffraction data will be required to determine the complete orientation distribution function. IMAT will be set-up for in-situ studies and processing, for example texture measurements in combination with strain measurements at non-ambient conditions (e.g. at elevated temperatures or under load), in-situ sintering or welding. The concurrent acquisition of transmission and diffraction data to study irreversible processes will be a major advantage of the instrument. The approach will allow for investigations of samples by imaging followed by a detailed diffraction analysis of the regions of interest by selecting any point within the 2D or 3D sample. By adding sample geometry acquired through imaging data, the diffraction scans benefit in terms of positioning accuracy, in order to obtain more focussed information about the stress state or the material’s composition at a particular point which often cannot be obtained by diffraction alone.

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