Anybody know where to find a 6B1000 7pin tube?

I've got a Superior Instruments (1954) model TV-50 Genometer signal generator that uses it as an RF oscillator.
I can't find anything on this tube. A 6bE6 sort-of works in it's place but not as well as the 6B1000.
What is it and where to get one or a cross reference.

Your question makes me think of the FM1000, but that is Loctal.
You may want to consider the mil-Spec version of the 6BE6 for stability. I can't think of the number right now, though.

Best Regards,

Bill Grimm