METHOD FOR PRODUCING POROUS QUARTZ GLASS BODY

PROBLEM TO BE SOLVED: To provide a method for producing a metal dopant-containing porous quartz glass body in which the dopant concentration distribution is small. SOLUTION: The method for producing the porous quartz glass body includes supplying a metal dopant precursor and an SiO2precursor from a central nozzle of a multiple pipe burner, wherein a plurality of gas supply nozzles are arranged concentrically, then hydrolyzing the precursors in an oxyhydrogen flame of the multiple pipe burner to form glass fine particles, and depositing and growing the formed glass fine particles on a base material. In the multiple pipe burner, the maximum point T1(°C) of flame temperature at a position corresponding to the glass fine particle deposition surface of the base material does not exist on an extended line of the central axis of the multiple pipe burner, and in the position corresponding to the glass fine particle deposition surface of the base material, in the case when a virtual line connecting a region (base end) where the flame temperature becomes the maximum point T1(°C) and an extended line (tip end) of the central axis of the multiple pipe burner is drawn, when the maximum point of the flame temperature on the extended line in the tip end direction of the virtual line is defined as T2(°C), T1-T2≥30°C. The multiple pipe burner is arranged so that the rotation axis of the base material does not coincide with the central axis of the multiple burner. The magnitude relation between the distance from the rotation axis up to the region where the flame temperature becomes T1and the distance from the rotation axis up to the region where the flame temperature becomes T2is adjusted corresponding to the dopant concentration distribution in the produced porous quartz glass body. COPYRIGHT: (C)2011,JPO&INPIT