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 part of the reason I've never bought a used Cs standard. Most likely it's a $$$ doorstop, and always will be. FWIW, -John ============= > weijiaz...@sina.com wrote: >> Hi all, >> >> I got an HP 5071A,but it did not work.I think the Electron Multiplier >> decay problem. I want to change Electron Multiplier of Cesium Beam Tube >> . >> where to buy the Electron Multiplier and how to replace it? Thanks. >> >> >> weijiazhen > > If you are not a CBT production line: > > "forget about it" > > On the other hand, if you are a CBT production line: > > also "forget about it" > > Back when HP/Agilent made the tubes, they welded them shut, baked > them out, pulled a vacuum on them, and sealed them, but did NOT > break the glass ampule that held the cesium. They then did various > tests on the CBT. A fair percentage of them did not pass. In > that case, they were sent to the machine shop and placed in a lathe. > Any expert machinist cut off the weld, which went around the tube, > without damaging the structure beyond repair. Of course, this > caused the high vacuum inside the CBT to escape :-) The CBT's > were then sent back to the CBT line for rework, etc. It is important > to understand that this was done with the cesium safely contained > in the ampule. If a CBT passed the initial tests, a firing pin was > used to break the ampule, using a magnet to activate it, IIRC. > > According to the CBT people, it was not practical to rework CBT's > that had the cesium released, let alone to rework used CBT's. > Used CBT's are even worse because everything is "cesiated". > > Rick Karlquist N6RK > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.