If many identical neon tubes are to be pumped, and if they fit into an oven (straight tubes are ideal here) then the oven pumping system is most suitable. One run with some 20 tubes can take 60 minutes, including the time to connect the tubes. That is 3 minutes per tube, hence in continuous production 480 tubes per 24 hours. Every time all tubes in the oven are filled with the same gas at the same filling pressure. Therefore it is necessary that all neontubes have similar characteristics. It is very understandable that series of cold cathode tubes are ideal to be pumped with an automatic oven pumping system.
Two advantages of the oven pumping method are that tubes can be annealed prior to pumping down, and that vacuum pumping at high temperature can go on for about an hour, resulting in a very good vacuum, as the pumping down time is an extremely important quality factor.
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