In the last years of serious tube research and design there was a new type
of cathode created, which was as efficient as previous types, but was
immune to this effect. Most of tubes designed to be used in digital
circuits were designed with long times with no anode current flowing.
We can't tell
Actually, tubes used in binary counters have a problem known as "cathode
poisoning" that is unrelated to the one of the nixie tubes. Apparently a
resistive layer is formed on the cathode when the tube is kept long periods
of time turned on but in "off" state, which renders the tubes useless for
