Sunday, July 10, 2005

Ahh, Ardbeg

Friday night I broke into my new bottle of Ardbeg. I had been saving it just in case I got to celebrate a new job. It was all that I had been hoping for. I had forgotten how great an experience it is. That initial sweet taste, and the follow up smokyness. The incredible peety aroma, yet no one thing dominating. It is like a great play, where each actor has a role to play, and each does so superbly. From The Complete Guide to Single Malt Scotch by Micheal Jackson, Ardbeg "skips sweetly along at first, then becomes mean and moody," an apt description I think.

Today the magnet went through it's test quench. Normally a quench is something that is naturally part of a magnet installation, but never planned. With the 900 system, however, the magnet is designed with an Energy Management System (EMS) which must be tested before installation. Essentially, there is so much energy in the magnet (remember two 40 ton trucks hitting a brick wall at 100 miles per hour) that if it were to quench accidentally it would destroy itself in the process. So the EMS is used to "safely" quench the system if it starts to quench. The EMS consists of a set of capacitor banks that remain charged at all times. The system monitors the potential across each section of the magnet coil constantly, looking for sudden changes, indicating a quench is about to occur. Remember the magnet is superconducting, so normally there should be no potential across the coil. But when a section becomes resistive, the potential increases rapidly. This induces a large negative potential in the next section as the quench spreads. The EMS system looks for this signal in the magnet, and if it detects it, it fires all of the capacitor banks, routing all the energy from the magnet into big quench resistors that can safely dissipate the power. By doing a test quench (i.e. manually setting off the capacitor banks), the system can be tested to make sure that it will work if it is required. Now that the test quench is out of the way, the magnet can be energized to full field, a process that will take a full week to accomplish. That is assuming that there are no "unplanned" quenches during the process.

Hopefully over the next few weeks I'll be able to finish up most of the work I have left to do from my post-doc. The timing of this job was particularily good as the major projects I signed on to do were pretty much wrapped up. We just need to get this manuscript out the door. Once I finish with that I'll start the transition to the new position. I'll likely be setting up a "facility blog" where I can discuss more formally the goings on in the facility and interact with users a little more. I'll set up a link to that when it's up for those of you who may be interested in these matters.

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