Imaging of small distortions in A15 “lattice” by electron microscopy

One effect of high energy nuclear radiation on A15 compounds has been postulated earlier to be a loss of translational symmetry of the lattice. We report direct evidence of such distortions in Nb₃Sn irradiated with high energy neutrons, using moiré fringes. The distortion is found to increase with increasing fluence, up to a fluence of 2 × 10¹⁹ cm^-2.