[Amps] Power-off tube cooling

[ka1xo at juno.com]

Is not the junction where the metal pins travel through the ceramic
base and/or glass of a power tube subject to a more rapid mean time between failure rate because of thermal stress?

Would not a power tube's internal metal elements use the pins as a heat sink, whereby the ceramic  in the sealant area will see a concentration
of heat from inside the tube be conducted down to a larger metal heat sink, namely the tube socket and componentry?

I know in semi-professional cinema projection the equipment requires the lighting device forced air to remain on after the device is extinguished, and this practice started with open-air carbon arc and made its way through the 10KW tungsten multi-filament days into the xenon-arc systems I see now.

It would seem reasonable that the example tube of the former posting to the reflector that consumed over one hundred amps to the heater would be a mighty heat sink and the cooling of the pins might be just the ticket to avoiding premature vacuum leaks around the pins.

HBM