Cultured quartz of low aluminum content from production sized autoclaves

Recent studies of cultured quartz radiation stability (or "hardness") have called for quartz whose Z-reqion alu~inum content is 1 ppm or less. A report of unusually high purity quartz grown in silver from devitrified, high purity, silica given at the 1982 Frequency Control Symposium tends to confirm the predicted advantages. During 1982 and 1983 two low-aluminum runs were grown slowly in unlined production-sized autoclaves at the Sawyer Research Products cultured quartz plant, supported in part by the US Air Force, usinq previously qrown crystals as nutrient. Three other low-aluminum runs were also slow-grown from selected high-purity nutrients. The EPR analytical results of these samples from five runs are shawn in the table together with details of growth conditions, nutrient used, and IR indicated Q capability.