CATHODE RAY TUBE PUMPING

The electron gun we described in a previous blog entry was mounted and sealed into the neck of a tube using an automated machine which comprised of a number of fixtures which moved around the carousel and revolved on their own axis.   At the first position, the tube was mounted top downwards in the top part of the fixture and the electron gun was mounted base downwards in the lower part of the fixture .    In the following photo, you can see the loading arrangement: -

 Operation of a lever moved the gun such that it entered the neck of the tube and the fixture then moved to a sequence of stations at which the bulb was rotated in a flame from carefully postioned gas blowpipes playing onto the join area such that the neck and gun were gradually fused together this leaving the gun seated into the tube with the pumping tube projecting downwards from the end of the neck - "sealing in" was thus completed. 

 At this stage, the glass was allowed to cool slowly to prevent heat induced stresses being left in the glass which had the potential to weaken the glass and hence pose an implosion risk at pumping - more on pumping in the next blog entry.