
MRI Scanner Superconducting Magnet Quench
Once a superconducting magnet is ramped up and fully magnetized, it literally takes no additional current or power to keep the magnet going. There's zero resistance -- that's the "superconducting" part -- so the current flowing in the magnet coils will run forever. That is, forever if the liquid helium cooling the magnet is kept cold enough, which is quite close to Absolute Zero. If the cooling system goes on the fritz, the magnet starts to develop resistance, which cause heat, which causes more resistance, and more heat, and so on until all the liquid helium gets hot enough to become a gas, which then erupts in a jet-engine-sounding event known as a quench. That's thousands of dollars worth of helium you see in the photo sequence above, going bye-bye.
The photo is of the GE MRI manufacturing plant where I used to work, and I myself saw a magnet quench much like this one. Unforgettable, much better than inhaling those balloons and talking like Donald Duck for 15 seconds. In a wide-open space like a manufacturing plant, there's really not much cause for alarm. But in a smaller space, the inert helium can displace all the oxygen and kill you. Several years ago a GE field engineer was killed by a slower, less spectacular helium leak at a customer's site. In a small, enclosed space it can sneak up on you pretty quick.
Remove it from the loud sound described as among the People of the individual during sleep, especially in the medical sense, the most common cause of snoring soft palate observed in adults, little more than normal growth of the tongue, the muscles sag and tension and blockage of the airway during sleep, losing little of the language titresmesidi
Posted by: horkes | 03/09/2011 at 09:06 AM
We have often repeated that the truth, because the error was also repeated in the propaganda, and not individual people but a large number of people publicity.Are you felt that it is right? I do not really think that, but can keep personal opinions!
Posted by: coach outlet | 11/03/2010 at 04:13 AM
Very interesting. Is the cost to keep the magnets cooled down worth the energy they create?
Posted by: Wristbands | 07/16/2010 at 04:55 PM
I guess there is no taste or smell to the helium gasses then? If so I would think the engineer would have been able to exit the infected area and seek help before succumbing to the gasses.
Posted by: Lee Pinsanetti | 07/16/2010 at 04:34 PM
I was wondering, what is the lowest % of helium you can have before a quench happens,i.e 60% 25% etc, and at what temperature (of the chiller) do you start to suspect a quench will happen
Thanks
Susan
Posted by: susan | 12/11/2007 at 03:44 PM
May i use the quench photo you have displayed at http://www.tommcmahon.net/2005/08/mri_scanner_sup.html for a research project at the university of southern indiana?
Posted by: Cody | 11/05/2007 at 12:07 PM
Fascinating information. I never realized that those magnets were always on. (And Strategy of bingo/excitement of chess is great)
Posted by: Jason | 01/16/2006 at 01:13 PM