We have three of these measurement boxes. One is being used to monitor system X, one is broken and awaiting repair, and the third has gone walkabout.
Category Archives: Lab Stories
Quote of the Day
Comes from a discussion of vacua; an ion gauge should provide a small amount of pumping, sufficient for a small system, but in case it doesn’t, one could place the system in (or just above) some liquid nitrogen, which prompted this gem about cryopumping:
At liquid Helium temperatures, even a cheeseburger doesn’t outgas much.
(originator unknown)
I Can Do the Can Can
The topic of discussion a few days ago was vacuum chambers, because we want to eventually trap ions, and these can be made to be pretty compact — you don’t need a very large vacuum chamber. In fact, you can get away with no external pump at all in the final configuration; after the initial pumpdown you pinch off the connection tube you activate a getter material inside the vacuum chamber (remembering, of course to put Bedevere, Lancelot and Galahad inside the rabbit beforehand, in order to take the French by surprise. Not only by surprise, but totally unarmed!)
How compact? Well, basically the size of a soda can. Which, of course, prompted a discussion of using an actual soda can. We ignored the problems of the hole in the can and the completely inadequate strength of a can, and instead focused on the problem of whether cans had a liner that would cause a problem with a vacuum. Something easily checked by a visit to Google, but we’re experimentalists, and a hacksaw blade was closer than the internet. We empirically determined the presence of the liner. It was only later on that one of us confirmed that a liner called Vinylite was introduced in 1934; the problem that prompted the invention was that beer in cans tasted just awful. (i.e. much worse than beer in cans currently taste)
The major problem the early researchers were confronted with, however, was not strength, but the can’s liner. Several years and most of the early research funds were spent to solve this perplexing problem. Beer has a strong affinity for metal, causing precipitated salts and a foul taste. The brewers called the condition “metal turbidity”.
Though I would not have been surprised if it read “causing precipitated salts and a foul taste. The brewers called the condition Genesee Cream Ale”
Along with that tidbit is a recipe for dissolving the aluminum to leave only the liner. It involved 6M KOH, so this is not something you want to try at home.
A New Group Meeting Experience
A new meeting experience on Thursday: a meeting with, essentially, footnotes. This was not a presentation, mind you — no rehearsed talk, no powerpoint, no written materials. Just an impromptu discussion, where someone used some ad-hoc terminology. Rather than deviate off on a tangent (or possibly a secant) and immediately delineate its origins, he waited until finishing the somewhat extended train of thought, and only then did he explain the etymology of the phrase he had used. I can’t recall that happening before, at least with the length of discussion involved. It was probably five minutes between the phrase and the explanation. I’ve only seen that in prepared talks.
The mention of footnotes then led into a brief discussion of David Foster Wallace (who apparently was very aggressive in his use of them)
Someone at the table: What kind of author is he?
Me: Dead
Our group meetings tend to meander a bit. But then, I’m usually a little punchy by Thursday afternoon, so I am an instigator of that behavior.
A Chip in the Big Game
Last week I stayed late to give a tour of our clock facility, and to show off the fountain, to some brass that were visiting. For me, tours like this are a little bit stressful, because this was more than just the gee-whiz—aren’t—we—cool tour (and tabletop-ish atomic physics makes for some pretty good gee-whiz) we give to some visitors. For those visitors, talking about physics is sufficient, and I’m pretty good at bringing the geek. For visitors who actually have a stake in what we do, I’m trying to make the presentation relevant to the job they do, above and beyond the “timing = navigation, because a nanosecond is a foot.” And really there is more to that message, because timing is also tied in with communication (and more importantly, secure communication) but because I’m the redundant backup for such tours, I don’t have a lot of practice at the high-level discussions. Which makes a feedback loop — because I don’t have a lot of practice to polish the talk (and I’m further down the chain), I don’t get called on to do this often, etc., etc. Iterate.
But things went well enough, and as the admiral shook my hand and thanked me, a coin was transferred into my possession. Challenge coins are a military tradition, that admit I had no awareness of when I was a junior officer in the navy, mostly because they are generally (or admirally) exchanged only when rubbing elbows with top brass of some sort. Wikipedia tells me the tradition probably dates back to WWI. There are coins that reflects one’s unit, and coins that reflect one’s job, especially if one has a job with a large degree of specialization. These are used as identification, and as with so many military traditions, they are often tied into drinking — if challenged to produce your coin and you don’t have it (or sometimes if you are the last one to do so), you are expected to get a round of drinks.
There are other coins that represent one’s command, and still others that are personal coins which will declare the rank of the giver. These can also be presented as a challenge when you’re sitting in a bar, with the owner of the coin representing the highest rank winning, and exempt from having to pay for drinks. The coin I got represents the Admiral’s office at the Joint Chiefs, rather than being a personal coin, so it does not show the rank of Rear Admiral (two stars). The frequency at which one gives out a coin is really a personal decision; I’ve read of flag officers who carried (or, more specifically, had their aids carry) a bag of coins with them because they handed them out so readily, and others who were very stingy. This was my first coin, and was probably given in appreciation for staying fairly late. A true cynic might think this is little different from the kind of cheesy awards you can buy (“You’re a Star” mug, “Celebrate Awesomeness” hunk of plastic or “Team Player” keychain) but I disagree. A coin — especially a nice coin — is not a bulk item, and has a nice tradition behind to back it up. I’m pretty jazzed about it.
Lab Chicken
I recently spent a while unwrapping and eating 64 slices of American cheese about a hundred individually-wrapped connectors, which is a pretty mindless way to spend a few minutes, although it’s better than mindless paperwork or training. Because I lost at lab chicken. Twice in one day, in fact.
Lab chicken, or some variant of it, is an informal game that’s been played out in all places I’ve worked. In its current form, it consists of trying to get someone else to do some tedious task of yours, through either luck or some cunning non-Baldrickian plan (in that it actually works), but not through overt threats or bribery. To the uninitiated, it might seem like an exercise in procrastination, but procrastination in and of itself does not usually invite participation and competition. (Procrastination is often its own reward — not doing an unpleasant or silly task, and often enough, the powers that be change their mind and cancel or scale back what was required. Plenty of positive reinforcement, even without the dispensing of food pellets.)
It’s common practice in our group that when you order something, you are responsible for unpacking it. This usually works quite well, because if you order something you are often the one who is going to use it — a replacement part, flange for a vacuum system, optics or something related — you ordered it because you need it to move along with your project. But sometimes you order parts in large quantities, because you are thinking ahead to the next several months of assembly. So the box may sit on your desk, waiting, until someone actually needs one of the components, and then they are forced to actually unwrap the rest and put them away. That’s what happened to me. I needed a certain connector and was handed the box of “many,” and ended up putting them away.
My other “loss” was when I went to sit down to assemble my little project. Someone had stored several cardboard boxes in the space below the lab bench where I was going to work. Taking a single box down to the recycling bin is a waste of time, so the challenge here is to pile the boxes up until it gets cleared. Since we had some sneetches coming through later on, the pile had to be eradicated. So I got stuck with that task, too.
A Little Smack
Laser Smackdown: The Most Amazing Use of a Laser?
Chad asks the question in general, but I am going to personalize it. I’ve had the opportunity to do some neat things with lasers, mostly related to laser cooling and trapping. I’ve trapped K-37, K-38(m), K-40, K-41, Rb-85, Rb-87, and Cs-133 (the first two of those being radioactive isotopes with half-lives of around one second) and in each case, made a slow atomic beam to send the atoms somewhere else so we could use them for whatever reason depending on the experiment. Making state-of-the-art atomic clocks? Pretty cool. I’ve made holograms, which are a not-too-shabby use.
But the neatest thing I ever did happened in grad school, while we were still building up to cooling and trapping. There was a science summer school in session, and our lab set up a demonstration: we took our home-built lasers and modulated the current being sent to them by tapping in to the output jack of a boombox. Then we sent the beam across the lab and onto a photodiode, and sent the AC output into another boombox. Music sent across the room on a beam of light! Essentially fiber-optic data transmission without the fiber, so we could show the students that blocking the beam stopped the music, and while this is standard (even boring) today and wasn’t really new even then, I thought it was the coolest thing I had ever done (to that point, anyway).
Empirical Data
There are some bits of dialog that just kill a conversation.
On Thursday I accumulated the datum that the phrase I might work better wearing lederhosen, but we’re just not going to find that out instantly ends the meeting.
(No, I wasn’t the one who spoke the line)
Progress
Since the Last Progress Report, I Have Worked on This Progress Report
This always takes much longer than it ought to, in large part because it’s hard to remember exactly when certain significant things happened, which leads to a lot of searching of my email trying to determine when various things saw print, and which of the available categories it fits in. I probably really ought to keep a running tally of my activities as the year goes along, but they tweak the form every year or two, so my attempts have always been thwarted– I end up spending a bunch of time working out how to convert from one version of the form to another.
I have to do monthly reports, and then I can choose my greatest hits from them for the annual report. At one point long ago the reports were weekly, but that got to heavily into minutia, which wasn’t particularly useful. There’s only so much you can report about aligning optics and tweaking lasers, and sometime no real progress is made at all, especially if you’ve stepped in some management and can’t spend time in the lab. All too often the reports go along the lines of
Week N: Discovered some anomaly.
Week N+1 Investigated anomaly; finally identified and solved the problem
Week N+2 Oops, no I didn’t.
When you finally do fix the issue, what you’ve reported is all of the path-dependent work you did, instead of the actual progress you made.
Grad School is like a Startup Company
Paul Graham: What Startups are Really Like
The cofounder is your thesis advisor. There are many points with a pretty decent correlation to life in grad school, at least for physics, and my datum.
I’ve been surprised again and again by just how much more important persistence is than raw intelligence.
Not that physics grad school is populated with dummies or anything, but persistence is mandatory.
I’m continually surprised by how long everything can take. Assuming your product doesn’t experience the explosive growth that very few products do, everything from development to dealmaking (especially dealmaking) seems to take 2-3x longer than I always imagine.
Ask a grad student how long until the get their degree, and you’ll probably get an answer like, “I just need to get this one bit of apparatus to work, get a little data, and then it’s thesis-writing time. I’ll be done in a year.” A year later, you will probably get the same response.
When I was in school, we filed a plan of what coursework we would be doing for our degree, which was reviewed and approved by your thesis committee. It had to include a certain number of research credits, which basically amounted to one year of full-time research. A friend of mine asked, “What happens if I finish sooner than that?” which elicited a round of laughter from his advisors. “We’ll deal with that if it happens.” He had done two years of classes at that point, and was there for 5 more years.