| 摘要 |
The method for producing and processing a preform (1p, 1s) comprises a preliminary process phase, in which silica grain (5a; 5b) is supplied into the interior space (110) of a silica tube (11) having an open upper end and a closed lower end (111), in order to obtain an unprocessed preform (1p, 1s ), and comprises a final process phase, in which the interior space (110) of the silica tube (11) is closed, a condition of reduced pressure is generated, the unprocessed preform (1p, 1s ) is heated with a final process temperature in order to fuse the silica tube (11) and the silica grain (5b). According to the invention the silica grain (5a; 5b) entering the interior space (110) is thermally treated during the preliminary process phase with an intermediate process temperature that lies under the melting point of the silica grain.
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