Method for producing doped quartz glass

A method for producing quartz glass doped with a first and second dopant, said method comprising:

• providing a suspension that comprises SiO2 particles in an aqueous liquid;
• supplying to the suspension a starting compound for the first dopant and a starting compound for the second dopant, wherein the starting compounds of the first and second dopants are added to the suspension in dissolved form;
• generating particles of, or particles of precursor substances of, the first and second dopants in the suspension as a precipitate of a precipitation reaction of the starting compounds;
• removing the liquid so as to form a co-doped intermediate product containing particles of the first dopant or particles of a precursor substance of the first dopant and particles of the second dopant or particles of a precursor substance of the second dopant;
• forming the co-doped quartz glass from the co-doped intermediate product by sintering;
• wherein the suspension has a pH, and the precipitation reaction is induced as a pH-controlled mixed precipitation;
• and
• wherein, before the supplying of the starting compounds, the pH of the suspension is adjusted such that, upon addition of the starting compounds, the particles of the first dopant and the particles of the second dopant or the particles of the precursor substances of the first and second dopants precipitate immediately.