Engineering question: Tube Camera Survivability

[old_tv_nut]

Originally Posted by ppppenguin

A problem that's affecting a few earlier camera tubes is helium ingress. The glass is permeable to helium and despite the low concentration in the air, there's a density gradient across the glass.

The beam travels a long distance at low velocity so even a farily small amount of gas will cause trouble.

Yep. That's supposed to be reduced by occasionally firing them up. I don't think I knew it's specifically helium, but that makes sense.