A second kind of diffuse scattering appears at these high doses which cannot be accounted for on the basis of a thermal origin but is probably related to scattering resulting from imhomogeneous lattice strains. It is suggested that these changes result from a reorientation of disordered regions which is assisted by the increased expansion of the lattice and the presence of ruptured silicon-oxygen bonds. The diffuse x-ray scattering halo associated with the amorphous material changes peak position, shape, and intensity with increasing dosages of irradiation. Amorphous regions enmeshed in the host lattice are identified in crystals that still possess long range order after irradiation with 7 x 10/sup 19/ neutrons/cm/sup 2/. After irradiation with 8 x 10/sup 19/ neutrons/cm/sup 2/ an inhomogeneous shear strain is observed in the extreme skewing of the (22.0) reflection which is interpreted as being due to the crowding of oxygen ion interstitials into the open c-axis channels. After doses in excess of 3 x 10/sup 19/ neutrons/cm/sup 2/ the damaging process is more complex since the volume change indicated by x-ray measurements of the host lattice becomes larger than the bulk volume change determined hydrostatically. The model which more » seems to fit these results best consists of point defects and slightly disordered regions which result in an elastic distention of the lattice. In this dosage range the volume increase is the same, as determined by x-ray and hydrostatic methods, and littie or no distortion is observed in x-ray diffraction patterns. Crystals irradiated with less than 3 x 10/sup 19/ neutrons/cm/sup 2/ expand anisotropically in a manner that is similar to the thermal expansion of unirradiated quartz. The structural effects of the irradiation follow at least two processes with doses up to 1.2 x 10/sup 20/ neutrons/cm/sup 2/. X-ray and density studies have been made on single crystals of quartz irradiated with fast pile neutrons at approximately 100 deg C. Foreign atoms and molecules can migrate through channels of this network. In conclusion, the cause for α-quartz lattice expansion and sample amorphization was also explored using XRD and Raman spectroscopic = 30 nm in size in the sample. Complete amorphization of quartz was observed at a fluence of 2 × 10 20 n/cm 2 (E > 0.1 MeV) using XRD and confirmed by TEM characterization and Raman spectroscopic studies. Moreover, an amorphous content was determined in the quartz samples neutron irradiated at 4 × 10 19 n/cm 2, with the greater amount being in the 52 ☌ irradiated sample. The lattice growth was larger for the samples that were neutron irradiated at 52 ☌ than at 95 ☌. XRD studies showed that the lattice parameters of α-quartz increased with increasing neutron flux. The changes in the α-quartz phase as a function of these two conditions (temperature and fluence) were studied using X-ray powder diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM), and the results acquired using these complementary techniques are presented in a single place for the first time. Quartz single-crystal samples consisting of α-quartz crystal structure were neutron irradiated to fluences of 5 × 10 18, 4 × 10 19, and 2 × 10 20 n/cm 2 (E > 0.1 MeV) at two temperatures (52 and 95 ☌).
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