Last week saw a foray into snow and rain, beams and bunker-like laboratories. Professor Dodd received her second award of beam time in 6 months (the first application took years!) and as a result, Sarah Butler and I got to travel to the Argonne Advanced Photon Source with her to watch and participate in a project. The project was comparing various copper alloy artifacts from three different places within the Persian Empire to see if manufacturing technology changed in some pattern with the advent of empire, and also the differing effects of imperialization on a central city and a formerly autonomous region. Examining the crystalline structure of the artifacts through XRD would produce information about forging techniques and degree of fineness, while elemental XRF analysis would tell us what kinds of minerals were being alloyed with the copper. At least that was my understanding. Most everyone working on the project held advanced degrees and had a much more legit knowledge of what was going on, either on the physics side or the archaeology side. Fully interpreting the data from XRD and XRF requires as much study as being well-versed in Persian history – but, as the title says, USC undergrads get to go wonderful places. Sarah and I actually gained a lot of experience working camera controls and “driving,” or operating the software that controls the laser beam.
To recap: I arrived at the Argonne Guest House (no tents here) on Thursday and bounced over to the synchrotron facility, where the rest of the project members had already been for a day and a half. The beam is housed in this storage ring of over a thousand meters, which nests in a Costco-sized circular experiment hall clad all over with postmodern white sheeting. I walked down a flight of stairs to Sector 1, commonly lent out to “users” from the public since Argonne is funded by the Department of Energy and by extension our taxes. As she put it, Prof. Dodd had gotten the equivalent of a quarter million dollars with her 72-hour beam grant.
People were patient, but patiently frustrated. They had already spent a whole day fussing with hutch cameras and the setup of the lasering platform, and a very intense kind of pent-up expectancy translated into a sourceless hum. Argonne’s beam scientists from last time were there again as were Prof. Dodd and Dr. Friedman, both Ancient Near East/Anatolian specialists, and new faces including two Toronto archaeologists and a conservator from the Oriental Institute. Dr. Friedman took us up to the rooftop upon arrival so that we could see the entire beamline, which was cloaked in white this time of year. From the balcony we looked in vain for the totally white deer, which may or may not have been collateral damage from a secret radiation incident. Inside she showed us posters listing which organizations had collaborated with Argonne, and what some projects were across the disciplines. If you go to the 2008 Argonne visitor’s book you can see her project involving metal bangles.
We went back down, hung around the hutch for a bit, and watched people make miniscule adjustments on a small rotating motor that moves the object to be X-rayed up and down. After a while, one of the physicists rounded up the newcomers for a safety orientation. I didn’t go with them, my training being valid from the summer, but this is the part where you get shown all the nasty, dangerous chemicals in pod-like lab spaces along the wall and great silvery tanks you don’t want to knock over. A guide walks you through the steps for evacuating, for calling for help, and what to do in case there’s a tornado (bathrooms are certified tornado shelters). Then they give you the instructions for beam usage: you go into the open hutch and push a green button, then another green button on the other wall, and listen to a robot woman’s voice say “CLOSING STATION THREE – PLEASE EXIT IMMEDIATELY” over and over again. Heavy pneumatic (?) blue doors slide closed, and then you can open the shutter that lets the beam out. The first time I kind of panicked when this happened and fled out of the room; after a night or two, everyone in their sleep-deprived loopiness usually falls to imitating the voice.
The first night shift was mine and two archaeologists’, which shows you the incredible amount of license given to us there – nobody was the least worried that we’d screw up the delicate scientific equipment, at detriment to ourselves or the beamline. One person sat in the driver’s seat, manning two keyboards under a panoply of 6 monitors and calling out numbers to the other two, who alternated between reading a K- and L-energy level graph (XRF), watching for faint rings on a black screen to appear (XRD), and capturing and renaming files (cameras). Out of sheer generosity the conservator, Laura, had stayed well into the a.m. preparing artifact foam pads for us, so the changing process was very simple: take artifact out, lift up new foam server with a gloved hand, stabilizing top of artifact with your index finger, and slide between metal posts on the lasering platform. Progress was slow-going but steady, and at 8 a.m. I walked back to the Guest House excited to find out later what new information had been gleaned while I slept.
When I returned, I was told that while I slept, the beamline had been bumped into not working for a little while, which Sarah can tell you about. But the second night went much more smoothly, and we found an interesting anomaly, higher concentrations of tin at the shaft and tip of Megiddo artifacts, as well as cleared up bizarre readings of strontium and some heavy atomic elements that had been worrying us earlier. Some extra beam time was given to us at the end of the 72 hours, which eagerly sopped up put our total batch count at 40 artifacts. Considering the data files (XRD and XRF) are huge, this will yield quite a lot of information! Anyway, that’s an abbreviated version of USC at Argonne version 2.0. It was a great experience, and though the Persian Empire is not my focus I am extremely eager to see what research comes of it.