Fig. 90: After an oscillatory shearing on the sample with a strain amplitude of the order of 1 the X-ray diffraction pattern is recorded (sample-detector distance 5 m, 1 Å wavelength):

a) in (kv, ke)-plane of the reciprocal (the vertical direction corresponds to the vorticity e direction and the horizontal to the velocity V direction)

b) in (k, ke)-plane (the vorticity direction is still vertical and the velocity gradient or shear direction is horizontal); this second spectrum is the signature of a pure f.c.c. packing of the micelles without stacking fault over several tenths of a millimetre in the gap of the Couette cell, probed with a 100 x 100 µm2 X-ray beam size.