Monday, October 22, 2012

Current research: All-nighters for science

Sometimes I run experiments at the Advanced Light Source.  You can read more about it here or here, but the basic idea is that there is a beam of electrons going around in a giant ring, just like a synchrotron particle collider.  But in a particle collider, they have to worry about losing energy to radiation; at the Advanced Light Source, the radiation is the whole point.  All around the ring, the x-ray radiation is used for a diverse number of experiments, from biology to materials science.

Anyway, the result is that thousands of scientists come every year to do experiments.  Even though there are a dozen different places around the ring where experiments can run simultaneously, "beam time" is in high demand.  So every semester there's this process where we propose experiments, and get assigned specific days to run experiments.  Typically, we get assigned 24 hour blocks.

So when I run experiments at the Advanced Light Source, that means I'm working for 24 hours straight.

Here's how a typical experiment might go:

Hour 1: I load samples into vacuum and wait for it to pump down.  I wait for the liquid helium to cool the sample.
Hour 2: I try to align the X-ray beam with the sample.  Is it not showing because it's not aligned or is one of the settings wrong?
Hour 3: The staff scientist comes by and instantly solves the problem we've been working on for the last hour.  We fiddle around with the settings to see if we can get the signal to look better.
Hour 4: Geez, I'm already tired, and beam time has hardly gotten started.  But finally, we can take our first data, a quick fermi surface mapping.
Hour 5: The computer crashes repeatedly.  Even the staff scientist is puzzled for a while.  I'm hungry, so I produce dinner from thin air.  Just kidding, I painstakingly cooked all of that food the previous night.
Hour 6: This data doesn't look quite right.  Maybe we can solve the problem by taking more data?
Hour 7: Maybe it would look better if we tried a new sample?  We spend an hour switching to a new sample and cooling it down.
Hour 8: We've learned from our mistakes, and this time it only takes an hour to get the sample in the right place.  It doesn't look much better than the previous sample though.
Hour 9-12: Finally, we can take our data again.  I sort of nod off, only staying sufficiently awake to start new scans every hour.  I heat up more food and try reading my book, but soon I don't have the short term memory to get through long sentences.
Hour 13: Apparently, the light polarization was all wrong, and that's why the data didn't quite look the way we wanted.  Good thing we figured it out early and didn't waste too much time.
Hour 14: I argue with my coworker over the best way to ration our time.  Better statistics, better resolution, more data points, it's all a trade off.  We take test scans trying to figure out our best options.
Hour 15-23: Now we start really taking data.  Strangely, I feel more awake now, even though I no longer have to think very much.  I do my physics homework.
Hour 24: We're done with our main plan, with one hour to go.  We spend 20 minutes arguing over the best way to spend the last 40 minutes.

Hour 48: We discover that all the data we acquired was useless because the sample wasn't cooled properly despite what the thermometers said.

Experimental work is frequently a shaggy dog story.