Growth and characterization of optical grade synthetic quartz

A method to position the seed and Z-region of growth out of the circulating micro-particle flux in commercial autoclave has been used to grow optical grade synthetic quartz. The number of solid inclusions is in the range of 0.02-0.03 particles/cm/sup 3/, depending on the bar. The observation of X-ray topographic contrast of (0003) reflection shows a much smaller Z-region lattice spacing (strain) in comparison with the seed. The dislocation lines are in their totality originated by the seed etch-channels, that means, they can be eliminated by using a better quality seed.