ABSTRACT
Pulsed source instruments designed to measure strains in materials, like their continuous flux counterparts, achieve this by measuring the normal distance d(hkl) between the {hkl} lattice planes within a small volume of the sample – the gauge volume. The strain at this point is then calculated by comparing this measurement with the corresponding d(hkl) within an un-strained part of the material (d0(hkl)). An engineering instrument on a pulsed source is therefore a specialised neutron diffractometer with three important attributes:
• an ability to measure the atomic lattice spacings to a high precision for multiple diffraction peaks,
• an ability to make such measurements on a small ‘gauge volume’ within the component under study, and
• an ability to position the gauge volume accurately with the component.
