Category Archives: Lab Stories

Just Doin' My Job

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On Thursday the department was treated to a pizza lunch by one of the senior staff (or his slush fund) in recognition of some recent events. Not too long ago, the remnants of hurricane Hannah swept through the area, and that meant a lot of work preparing equipment that’s exposed to the elements for the onslaught — there are various antennae and support equipment that have to either be stowed or battened down (arrr, love the nautical-speak. Don’t forget, today is Talk Like a Pirate Day)

Now, that’s a lot of work … for somebody. I’m in R&D, though, not operations. And while I’m happy to help when called upon, my main task in these situations is to stay the hell out of the way and let others do their respective jobs. Which I did exceedingly well.

The pizza was quite tasty.

Here's What's Happening on the Aloha Deck

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Because of the timekeeping implications of what we do in the lab and especially so because of the gee-whiz nature of table-top-ish atomic physics, I’m sometimes called upon to give (or assist with) lab tours to various visitors. Sometimes it’s scientists whom we’ve invited, and those are usually the best because you get to discuss interesting (to us) topics, and the value of the information exchange can be fairly high, exceeded only by workshops and conferences. But often enough it’s someone whose importance is on the bureaucratic side of the coin (i.e funding), or worse, whose importance is not at all apparent, though the powers that be have assured us that it’s necessary. Those can be more of a chore, especially with someone without a technical background and who is only doing it because (like me) they were told it was important. Then it’s an issue of how quickly one wants their eyes to glaze over. We can really shovel the geek.

So anyway, I helped give a lab tour on Wednesday. And let me tell you, it was NOT one of those that falls into the “chore” category.
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The Right Tool For the Job

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There’s always a right tool for the job, or so some people say. It has been observed that vice grips are never the right tool for the job, but they are indispensable because they are the wrong tool for so many jobs.

(tightening a screw in a tight space with a phillips bit held by vice grips)

One More Thing . . .

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The other thing that struck me about bait-and-switch was this

I gravitated toward a scientific life with fantasies of sci-fi movies running through my head, with large machines emitting lightning at the flip of a huge Frankenstein-type switch, or several people poring over softly-glowing computer screens as an experiment produces fantastic data in real-time, and great discoveries are made. I thought this kind of thing actually happened even as I started grad school (even if I had never seen it in my various research summers…)

It doesn’t happen often, but it does happen (depending on your definition of “great”). Back in my first postdoc, at TRIUMF, we trapped radioactive potassium atoms for nuclear-decay tests of the standard model. Or, more precisely, we planned to do this, since the research had progressed only to the point where stable potassium had been trapped when I started working there. Not too long after my arrival we were scheduled for a few stretches of beam time, with an appropriate target to produce the radioactive isotopes we were trying to trap.

Since these were radioactive isotopes, the exact frequency for trapping them was unknown, though the presence of stable isotopes meant (in principle) that the isotope shift could be calculated to some degree of accuracy and narrow down the range of frequencies for the trapping and repump interactions. Since the linewidth of the transition is somewhere around 5 MHz, and you should be able to see a trap with a laser detuning of somewhere between a half a linewidth and several linewidths to the red of resonance, we set up to scan in discrete steps of several MHz, pausing at each step to look for fluorescence at the center of the trapping region — literally looking: we integrated the output from a CCD camera and displayed it on a computer screen, along with a graph of the total fluorescence.
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Conferences

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FemaleScienceProfessor discusses the pros and cons of talk vs. poster, confounded by the politics of being involved in the conference. Physics conferences in particular have a certain breakdown that’s mentioned over at Uncertain Principles, that being invited talks, contributed talks and posters. It was my impression that posters weren’t nearly as big a thing in the particle physics community vs the AMO community, during my postdoc at an accelerator lab some years back — I was gearing up for an atomic physics conference, to discuss the double-MOT system we had, and how we transferred the atoms, and the particle men acted like they weren’t familiar with the concept of a poster session.

One aspect of talk vs. poster is how important is it to be seen, as opposed to how important it is to get experimental details out (as much as you can do that in 10 minutes or so). In that case it was a description of an apparatus and not any real experimental results, so a poster made sense. When we had some experimental results, I gave a talk, and that gave the attendees a chance to see me and associate my face with that experiment — several or many dozen, as opposed to a smaller number that might have dropped by a poster. (Of course, a smaller number isn’t so bad when it includes a Nobel prize-winner or winner-to-be).

What I remember about that particular talk is that the program listed the talks as being 15 minutes long: 12 minutes of talking, with 3 more for questions. During the announcements preceding the plenary session, we were informed that that was a typo in the program, and the talks were actually just 12 minutes total: 10 for presentation and 2 for questions. The poor people giving talks that day had no chance to revise things and cut down their presentations, and everything ran late. I at least had that evening to make adjustments and drop a slide to bring my talk in in the allotted time.

I Am Static Man

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I’m shocked, shocked, to find that I’m getting shocked. My adventures with static electricity.

It’s winter, it’s dry and that makes for pretty good sparks. I haven’t been going to the gym the last few mornings (recovering from being unwell) but have been going to work, so that means peeling off some layers of cotton clothing in the dark. And that means some static electricity. I must roll around a lot in my sleep or something, because there are a lot of sparks a-flyin’ when I take my socks off, and also my sweatshirt. I used to have a blanket (when i was about 10) that would spark nicely if I covered myself and did a bicycle motion while on my back, so my stocking feet continually rubbed on the blanket; since I was covered it was dark, and there were lots of sparks. Slippers on the carpet were always good for sister-annoyance, too, back then. Or just scuffling along holding a fluorescent bulb and watching it flash occasionally, if you could find a dark room.

At the lab, I’m the one who usually peels off the sticky mats in the lab area. (I must have the lowest threshold of being bothered by them being dirty, partially conditioned by being the one who had to clean the optics before we transitioned to semi-sealed modular systems with lots of connecting fiber). Big, big zaps with those. You can get a similar result if you ever buy plexiglass that’s encased in plastic wrap. I bought some big ones (72″ x 40″ to cover some hallway posters near my office), and there were some packing peanut scraps nearby. Once you charge those puppies up, there are some styrofoam pieces that have a huge charge/mass ratio, and simply will not leave your hands until you’ve thoroughly discharged yourself. I had one that was just on the threshold, so when I flicked it off my hand, it would separate a little bit, but not far enough for the gravitational force to be larger than the attractive electrostatic force, so it would float back. Minutes of geeky fun.

For Christmas I got a shirt that’s made of teflon. Partially, at least. The instructions say not to use a dryer sheet with it and this shirt tumbling in the hot dryness really generates the static. And boy does it cling. The first time in the dryer it picked up some serious lint, and I had trouble picking it off because of the amount of charge — I pulled a small piece of string off of it, and when I tried to drop it in the trash can, letting it go about a foot away from the shirt, it flew back to the shirt. More minutes of geeky fun with that. I hesitate to admit that recently when I was ironing and generating some static charge, I empirically reminded myself that the ironing-board pad does not cover the edge of the ironing board, which is just below waist-level. I experienced a dramatic lowering of the potential difference between the ironing board and me, via the part of me closest to the exposed metal. (If you can’t paint a mental image of this, tough. I won’t draw you a diagram).

The Comfy Chair, er, MOT

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Over at Uncertain principles, Chad talks about how Nobody Expects Bose-Einstein Condensation, i.e. while the phenomenon had been predicted, the enabling technology was serendipitous.

What really made [magneto-optic trapping] take off, though, was that people figured out you could get the laser cooling wavelength for rubidium from diode lasers. And diode lasers are manufactured in mass quantities because they’re used in CD players, laser printers, and other commercial electronic devices. So, rather than needing to spend a couple hundred thousand dollars to get a dye laser system up and running, you could get a working laser system for a couple of grand.

And it’s true. The main enabler was the availability of diode lasers. And their ability to be tuned electronically and thermally. Ah, two! The the two main enablers were their availability and their ability to be tuned, and their susceptibility to optical feedback. Oh, three! The three main enablers were their availability and their ability to be tuned and their susceptibility to optical feedback. Hmmm. Among their advantages are such diverse elements as their availability and their ability to be tuned and their susceptibility to optical feedback, and a nice red color. Damn.

The main enabler was their availability. Blah, blah,blah.

OK, I’m kidding a little, because without the technical advantages, who cares if it’s available? But it’s an excuse to do a Python bit, and talk about the other things.

Laser diodes are pretty neat, though somewhat fragile. In the days of building my own systems, I never knew one that died a natural death-from-old-age. They all got blown up somehow, and I wish that had been in the days of digital cameras, because I recall one that looked cool under the microscope, with one facet blown off but still the piece still hanging there, attached to a tiny wire that was part of the circuit. You had to remove the can that surrounded the diode before you could mount them in our homemade system, and that took some practice. But there were usually some dead or otherwise useless diodes around for practice for newcomers to the lab.
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Moving Day

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When you can’t grab more real estate, you make more room in the lab. Four physicists move two optical tables, and nobody gets injured. Who’d have thunk it?

Officially, not really. This is all a gag, a spoof, a put-upon, since somebody, somewhere might frown upon the kind of do-it-yourself attitude of four unsupervised physicists playing with heavy equipment. So here’s what did not happen:

Our bundles of joy need to be placed where there is sufficient overhead space for assembly, and that meant some reshuffling of the lab, and that meant moving optics tables. Big, heavy brutes. Fortunately we discovered that the heavier one had casters built in to the legs, and were able to move it quite easily. Only a few hours of bundling up cables to make sure we didn’t overtension anything, and that table only had to be moved a few feet, so many of the cables stayed in place.

Moving the second table was a lot more involved. Continue reading →