Back when I was a grad student at NIST, we had a large frame argon ion laser that put out 10-15 watts of green light that we then used to pump a Ti:Sapph laser to produce the infrared light we used for laser cooling. This particular type of laser had a small design flaw-- the energy needed for laser operation was pumped into the medium by exciting a plasma discharge in the tube using a high-voltage filament, which was coiled around the beam line. Over time, the filament would soften slightly from the heat of the plasma, then droop into the beam line, and mess up the laser mode, rendering it useless.
There was one stretch, around 1997, when we went through three laser tubes in one year (two of them from the filament droop problem, the third from something unrelated). As the tubes cost something like $20,000, this was a non-trivial matter (this was before we were working in the Infinite Money Limit). When the third one went, we had Bob the laser tech out to confirm the problem, and he suggested a simple solution that kept the tube running for another six months:
He flipped the tube upside down. The filament became a problem because it sagged down into the beam, but rolling the tube over switched "up" and "down," and it took some time for the filament to start sagging in the other direction enough to cause a problem. Flipping the tube put the high-voltage leads on top of the tube, instead of on the bottom, but that wasn't a problem unless you opened the case, and other than that, everything worked just fine.
Bob told us that he had flipped a tube three times for some other research group, and that each flip cut the working time roughly in half-- the sdcond flip bought three months, the third a bit under two. By the time that our tube started to be a problem again, we had arranged for a replacement, so we never tested that, but it's always struck me as a neat and low-tech solution to a high-tech problem.
Which brings me around to the "Dorky Poll" part of this:
What's your favorite example of a low-tech solution to a high-tech problem?
Science abound with ingenious little tricks that people use to get around the quirks of their sophisticated apparatus. What's your favorite?
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Well, I don't know if this is exactly what you meant, but:
We analyze iron ore samples a lot in our lab, and the first step is dissolving it in hot hydrochloric acid. Originally, we used Corning laboratory hot plates, which cost upwards of $300 apiece for the large ones (note that this is without magnetic stirring, that costs extra). Unfortunately, acid fumes get into their workings, and corrode the heating elements, so they only last for a few years. After fruitlessly trying to repair three of these, I suddenly realized: hey, why am I using these expensive hotplates in the first place? Does Wal-Mart not stock electric griddles? Yes, they do! And not only are they only about $30 each (a tenth the cost of the laboratory hotplate), but they are bigger (so I only need one instead of three), coated with teflon (giving excellent chemical resistance), and have a runoff gutter to catch spills in a little plastic tray underneath! As it turns out, it works great, and actually heats *more uniformly* and *with better temperature control* than the expensive laboratory hotplates! I'm assuming that it will still have the acid corrosion problem, but hey, even if I have to buy a new one every year (which I probably don't, it's going on two years old now), and even if the expensive laboratory hotplates lasted 10 years (which they don't), it would still be the same price as one of the expensive plates - meaning that it is still actually cheaper, because I only need one instead of three!
Yeah, that's the same basic genre. The local equivalent was replacing a big HP frequency synthesizer and amplifier that we were using to drive a plasma discharge with a $50 CB radio from Radio Shack.
Huh. Our 10-15W argon ion laser that we use to pump our Ti:Sapph -- which we use for laser cooling -- has that exact same problem. The sagging cathode, I mean. (It's always weird to me that other people do what we do.) But I never thought of the "flip it upside down" solution.
I've got a feeling that's the kind of cheap solution my advisor will love -- I just hope he's willing to pay our laser tech Jeff to do it, 'cause I don't wanna mess around with those high voltage lines back there. Fortunately, ours has been sagging very slowly over the last year or so, and might be able to hold out until I graduate -- but I'll pass on the idea to the next person, if so. Thanks for the tip!
I never thought of the "flip it upside down" solution.
We had joked about it before Bob suggested it, so it was an amusing surprised. "H, ha, ha-- wait, you're serious?"
It worked great, though. It's not a permanent solution, but it'll get you another several months, which can be long enough to scrounge up funding for a new or refurbished tube.
(It's always weird to me that other people do what we do.)
Even weirder than hearing about people doing the same thing that you do is knowing exactly who the Jeff that Mary refers to is! I have to admit that I don't do laser cooling but I am nearly 100% certain I know your laser tech b/c of our own, and old, Ar ion's.
I would simply like to note that blue-tac gives a good low-cost combination of adhesion and electrical insulation -- although it does scorch at high temperatures (and smells nasty).
The song parody that I've half-written in my head would be on topic here, so let's try the first verse. The tune is "Copperhead Road" by Steve Earle.
Well, my name's Robert Stanley Dare
My job is building space flight hardware
I stayed in school and got a Ph.D.
Working late at night 'till my eyes couldn't see
I needed a conductor in high vacuum
And that's what set me on the path to doom
The guys in the lab said this tape was really neat
The adhesive doesn't outgas and it dissipates the heat
I went in the chamber, put it on like I was told
And I took the first step down Copper Tape Road
My favorite low-tech solution to a high-tech problem: saying "it's not my fault" when the Millenium Falcon won't make the jump to hyperspace.
And if I'm not dorky for saying that, then I don't know what is.
I use black electrical tape to cover flashing 12:00 on my betamax (keep in mind, I am a liberal arts major historian).
Actually, what crept into my mind was the great debate between using a beer can or a genuing BMW shim for motorcycle handlebars in the classic book, "Zen and the Art of Motorcycle Maintenance."
I've got a good one from my grad adviser Eric C. When he was a grad student, he needed to chirp a laser frequency for cooling, but didn't have an appropriate acousto-optic modulator or perhaps a good frequency ramp (back in the day, if you remember before DDS, it was hard to make a chirp). He found that there was a particular way he could bang on a particular mirror mount with a wrench so it would give the right kind of chirp. Now that's low tech!
I remember one of the older techs at my lab telling me that he used to have to rotate their stock of TIROS image orthicon tubes to keep them from getting out of alignment. TIROS was an early weather satellite, perhaps the first, so this was all very high technology. I assume that the image tube was aligned with the rocket during launch, and once in microgravity the tube elements would no longer deform.
An early version of this low tech solution was in the high tech, for the 17th century, riddling of champagne. Fermenting champagne produces a lot of sediment, but it's tricky to work with carbonated and pressurized wine. You can try filtering, settling and decanting, but every time you fuss with the champagne, you lose bubbles and flavor. The low tech solution was to store the bottle upside down and rotate them regularly so that all the yeast and cruft winds up at the bottle opening. Now, all you have to do is open the bottle for an instant and let the cruft blast out, then reseal it.
Duct tape...enough said.
I was pumping on the isolation vacuum for one of our low temperature probes; it gets pumped down infrequently because it is well sealed, this time was because when the graduating PhD student that built it was showing me how it worked he confused the safety release valves on two chambers and pried it open. There turned out to be a leak in a joint in the arm between the valve and the flange which would require intensive re-machining of the parts, I taped a latex glove around the joint, problem solved.
Also, this week actually, another student in my lab lost their best/favorite/most reliable sample in a 125 L LHe dewar, it fell of the probe during a dip test. Retrieval: a flash light and some duct tape wrapped around a metal rod, sticky side out. Otherwise it would have been lost.