[time-nuts] HP 5071A Electron Multiplier of Cesium Beam Tube

Lux, Jim (337C) james.p.lux at jpl.nasa.gov
Sun Sep 6 17:23:10 UTC 2009

On 9/6/09 10:04 AM, "J. Forster" <jfor at quik.com> wrote:

> Cesium is pretty reactive and could likely be stripped off chemically and
> the CBT tube cleaned.
> People can make simple triodes at home (with a lot of stuff). There were
> guys 'rebuilding' CRTs in the late 50s at home. However a CBT or other
> things with electron multipliers are FAR from a simple triode. You not
> only need exquisite vacuum technique, but also to be able to activate the
> electron multiplier. These are non-trivial things to do, even for large,
> expert companies. I was told by a guy at Varian that they typically did
> three tube starts for every one delivered on image intensifiers, which
> have MCP multipliers.

This is true on a lot of high performance vacuum/ion devices, like
Travelling Wave Tubes.  Start 10 to get 3 at the end, especially for a low
volume design;  a production line doing a run of dozens might get better
yield, but there's a lot of art in the process.  You can do some rework at
various points to get parts to start another, similar to what Rick described
with cutting the weld apart.

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