Tubular composite body of quartz glass and method for producing and using the same

A method for producing a tubular quartz glass composite body in an outside deposition method comprising the following method steps:

• (a) Providing a substrate tube which has a continuous through-opening running coaxially with a substrate tube longitudinal axis, a substrate tube outer diameter, a substrate tube inner diameter, a substrate tube wall thickness, a substrate tube outer lateral surface, and a substrate tube inner lateral surface,
• (b) Rotating the substrate tube about an axis of rotation running coaxially with or parallel to the substrate tube longitudinal axis,
• (c) Depositing SiO2 particles on the outer lateral surface of the substrate tube by means of at least one deposition burner to form a composite (1/9;
• 21/9) consisting of the substrate tube and a SiO2 soot body,
• (d) Sintering the composite (1/9;
• 21/9) by heating at a sintering temperature to form the tubular quartz glass composite body (100),
• wherein a substrate tube is provided which consists at least partially of quartz glass of a first quartz glass quality, and that the soot body consists of quartz glass of a second quartz glass quality, wherein the first quartz glass quality has a material-specific viscosity at the sintering temperature that is higher than the material-specific viscosity of the second quartz glass quality.