Measurements of diffuse x-ray scattering from $\alpha$-quartz single crystals after irradiation with 3×${10}^{18}$ fast neutrons per square centimeter are reported. The neutrons create defective regions of mean radius 10 Å, concentration 13.6×${10}^{-5\mathrm{}}$, and a volume change per region of 29 mean atomic volumes. The crystalline matrix is heavily strained by the defective regions and the symmetry and magnitude of the strain field is determined. These regions, which are most likely amorphous, contain the tunneling centers responsible for the recently observed phonon echoes.

• Received 12 November 1980

DOI:https://doi.org/10.1103/PhysRevLett.46.261