Gremlins

09Apr08

There is something I learned very early on in my life as an experimentalist.

If your experiment is running well, keep running until you are done. If it keeps screwing up, quit for the day and come back another time.

The first part has kept me in the lab from before sunrise until after sunset, with nothing but a crappy vending machine diet to sustain me. The latter has probably saved numerous expensive pieces of equipment. Once gremlins begin to show up, you have to leave. They won’t stop playing until something goes up in smoke.

There is a wide and catastrophically deep chasm between theory and experiment. Theory says that there are but a few variables that you have to deal with. Some of them you control, others you observe, and all are explicitly relevant to what you’re doing. That’s a great lie, of course, because the theorist did not foresee that you might be using a field scope that’s not grounded, so amplifier’s baseline keeps floating away. Or that dust on the lens tends to explode in the beam, sending a deadly crack through the whole optic. Or that a Gaussian beam always clips on the lens – unless you can afford that gorgeous four-inch aspheric, which you can’t.

Experimental work is as much about gut and instinct as it is about knowing your field of science. Which, by the way, is much wider than they tell you. I consider myself to have a decent education in physics and optics. However, to be a good experimental physicist I also had to learn – on my own, haphazardly along the way – programming, circuits, machining, chemistry (mostly solvents), CAD, statistics, signal analysis, all kinds of arts and crafts.

That is, of course, on top of being sharp with physics. After all, once you actually manage to squeeze a meaningful response from your setup – suppressed the noise, block stray reflections, fixed code bugs, learned to discriminate random line events from signal… – you have to figure out what does it mean physically.

Which is, of course, exactly why I love this so much. Who else can claim such a triumphant victory over something that would mean so little to anyone outside of the room.

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