Transmissive end seal for laser tubes

In a transmissive end seal and window for a laser plasma tube;

• bell means having an opening in one end of said tube and having a surface about said opening in the form of (a conically and) an outwardly facing opening (flare) flared portion adapted to receive a light transmissive window therein, window means adapted to be placed into said flared end of said bell means for forming sealing engagement therewith in closed relation against the surface thereat, said window means having a peripheral surface shaped to conform with and to mate with the outwardly flared portion of said bell so that said bell means and said window, when urged together, lie in contact therebetween throughout the closed path defined by said flared portion, glass frit forming a thin bond between said window and said end bell means about said path, said members being attached by being urged together in the presence of said frit and subjected to high temperature baking so as to melt said glass, which is thereafter cooled, said window means being constructed of a material having a high purity crystalline structure undamaged by, and transmissive to the radiation developed within said plasma tube, said window means having enhanced thermal conductivity due to its crystalline structure.