Patent ID: 7159418

Claim:
A process for producing synthetic quartz glass, comprising: feeding oxygen gas, hydrogen gas, and a silica-forming reactant gas from a single burner to a reaction zone, flame hydrolyzing the silica-forming reactant gas in the reaction zone to form fine particles of silica, depositing the silica particles on a rotatable substrate in the reaction zone to form a cylindrical porous silica matrix wherein during formation of the porous silica matrix, the silica matrix and the flame of reactant gas from the single burner are oriented to define an angle of 100°–110° between their respective center axes so that the entire cylindrical porous silica matrix has a density of 0.1–1.0 g/cm 3 with a uniform density defined by a density distribution within 0.1 g/cm 3 , and heating and vitrifying the porous silica matrix in a fluorine compound gas-containing atmosphere to form a fluorine-containing synthetic quartz glass.