FIFTH CANADIAN CONFERENCE ON NONDESTRUCTIVE ... - IAEA

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incident x-ray
beam
detector I incident
'x-ray beam
letector 2
Fig. 3. Representations of the u-w plane of Fig. 1 showing the
geometry of: A - the single exposure technique and B -
the double exposure technique for the measurement of
stress along the "u" direction using lattice parameter
measurements m, and m 2'
incident x-ray
beam
Fig. 4. Representation of the u~w plane of Fig. 1 showing three
diffracted beams, d.. , d and d~, for a given incident
beam direction. That corresponding to the centre of the
diffraction profile, d„, arises from lattice planes
normal to m„ while those corresponding to the high and
low angle tails of the profile, d. and d,, arise from
lattice planes with normal m. and m., respectively.
Because of the reflecting geometry, the angular separation
of the diffracted beams is twice that of the plane
normals.
m,