Rigaku high voltage tank

From: William G. Scott
Date: 27 September 2011 03:15


Hi Citizens:

We seem to run through high voltage tanks on our Raxis IV like guano goes through a goose.  Has anyone else had this problem, and, more importantly, what is the best way to protect them.  I am assuming it might have something to do with our electrical supply, which is a bit unreliable.

Also, does anyone have an extra used functional one they want to get rid of?  We've run out of 7-11s to rob to pay for this, and our friendly and helpful radiation safety staff think the best way to deal with this problem is to hack apart the power cable, so it is a current (so to speak) source of frustration.


Thanks in advance.

Bill


William G. Scott
Professor


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From: Patrick Loll

Bill,

What do you mean by "high voltage tank"? When I hear this term, I think of the oil- (and PCB-) filled tank housing the transformer on an old generator; but there's nothing like that on the R-Axis. Do you mean the blue box housing the detector controller? If so, then I can tell you that we've had ours plugged into a 1000 VA UPS (APC Back UPS Pro) for 10 years, with never a glitch (and I'm told that Philly power is not pretty).

If instead you're referring to the high voltage tank on the generator, then I have no idea of what to do (although replacing the power cable doesn't sound like a bad idea)...you'd probably need to steal an entire 7-11 to pay for a UPS large enough to condition power for that.

Pat

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From: Artem Evdokimov

Are you indeed referring to the oil-filled high voltage transformer core in the older model generators? (Newer ones tend to use solid state voltage multipliers). I recall that there were issues with those things that were eventually traced to elevated humidity. Now, that was humidity around 80% which should not be the case for most systems these days since most of us seem to prefer humidity controlled environments (for the sake of the cryostreams) but it might be worth checking some local leaks etc.

One more reason that the tank transformer might go bad would be inadequate matching between power input and drain, especially high-drain situation caused by an undetected high current (like a parasite current too weak to cause arcing, but strong enough to damage transformer over time). Did your/Rigaku's engineer check the voltages and currents in the tube tower? Do you have the option to record currents while no one is attending the instrument (in the even that the problem is intermittent)?

Artem

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From: William Scott

Yes.
That sounds much more sane.
Well, I'm at DIY-U, so this very likely is a potential source of the problem.

We have to supply our own hamsters for the electrical generators, too.
I don't think anything like that was ever done, but I am not sure.  We shipped it back
to them, and they need more money to continue diagnosis, so we are probably
just going to cut our losses on this decade-long nightmare.

William G. Scott

Contact info:
http://chemistry.ucsc.edu/~wgscott/