Gas passageway having selectively acting penetration surface and methods of making the passage area

The invention relates to a gas passage (1) with a selectively acting penetration surface consisting of quartz, quartz glass, pyrex glass or the like; in order to provide penetration surfaces which are relatively thin on the one hand but will withstand relatively great pressure differences on the other, it is proposed that the selectively acting penetration surface take the form of a plurality of adjacent windows (5).