Monday, February 27, 2006

Working with magnets

For my work, the office I work in is right next to the MRI room. I didn't know that much about MRI until now, especially since I had to take a training course. There was a problem with the magnet in the MRI, so they had to shut it down. This is a much larger undertaking then I had realized. The magnet is powered by a super conductor. This means that the magnet is running 24/7 even when no one is getting scanned. The super conductor must be kept as close to absolute 0 as possible (0 degrees kelvin, they usually are at 1-2 degrees) to do this they use liquid helium, 90 liters worth. When it expands to as gas multiply that number by 140, it was pretty loud. Once it was fixed they used liquid nitrogen to get the container cold enough before replacing it with the helium. They forgot they left the compressor on and froze the nitrogen solid. When every thing was back up and running, no one was used to having it back on and they brought a "partially safe" camera to close and it flew across the room to the center of the magnet. (It is a good thing no one was being scanned since that is usually where the brain goes.)
The training session that I took mainly showed a lot of videos of floor buffers stuck to the machine. It is pretty sobering when the guy teaching the safety course has a bandage around his hand where he got sliced from the camera getting ripped out of his hand.
So there a lot of wire mesh over windows and brass pipes everywhere to try to deal with the magnetic field. This is of course is the exact opposite of what someone wants when troubleshooting computers. Supposedly there are supposed to be no affect on the computers, but I know that while the magnet was offline there were less bugs.

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