OK, getter outgassed when activated for last step and poisoned the cathode...
Your vacuum was not high enough for dispenser cathode activation. Quite simply, if you have rubber tubing on high side of vacuum station you will NEVER achieve good enough vacuum to activate cathode.
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Diffusion Pump oil residue will ruin the cathode surface unless trapped by dry ice or LN2.
Your vacuum never was good enough.
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Try this, because the tube is not in an oven, it would outgas immediately on start anyways.
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This is not like a vacuum tube, getter is a NOT thing you want to run once you add the argon fill.
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Looks like nice version of BeO tube design invented by US Air Force and Dr. William Bridges right down to using SP magnet design.
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Following procedure is ONLY for tubes with external gas return and thin BeO bore. Using this on post 1969s tube designs will CERTAINLY kill the tube.
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EDIT!
PROCEDURE REDACTED AFTER VEWING BY LASERBUILDER !
EDIT
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Last edited by mixedgas; 08-17-2018 at 13:26.
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...