[time-nuts] CS reservoir depletion

Tom Van Baak tvb at LeapSecond.com
Thu Jan 13 05:54:58 UTC 2011

> Now that we are discussing how to restore Rb lamps. 
> Has anyone given any thought to refilling or refluxing the Cs in depleted Cs tubes?

Oh yes, after I ran into my first dead Cs and found the
price of a replacement tube, you bet I wondered if they
could be refilled. I mean, the same hp also made printers
and you can refill them. What could be more natural. But
a couple of events over the years dashed all my hopes.

First I got my first opened Cs tube, from an 5061A that
Corby had. I have no idea how you'd open one, do the
brain surgery, and put it back together with the same
purity and mechanical precision that it first was.

Second, running out of cesium is not always the problem.
Think about where the cesium goes. When a printer runs
out of ink it's because it has printed tens of thousands of
pages. The pages take the ink with them and the printer
stays fairly clean. But where does the cesium go? It's all
still inside, every single atom of it. On the walls, on the
magnets, in the getter, and stuck on the dynodes of the
electron multiplier. So even if you could add more Cs to
the oven on one end, perhaps the harder job would be to
clean up all the cesium residue that's everywhere else.
It would be like adding more and more fresh oil to a car
but never emptying the oil pan.

Third, I got a tour of the hp factory in Santa Clara where
the tubes were made. I was humbled. The clean room, the
precision, the tiny EM, the vacuum stuff, the oven assembly,
the one-time diaphragm that seals the oven pin hole, the
wiring, the testing, the people, the decades of knowledge,
the infrastructure.

Instead what would be fun is for someone to try to make
their own tube. Save yourself some work and re-use all the
electronics of a 5061A. But make your own tube. Even
re-use as many parts of an existing tube as you want. But
make your own instead of trying to put Humpty Dumpty
back together again.


More information about the time-nuts mailing list