Re:Metal chair near MRI machine
by mbateman on Tuesday June 08, 2010 @07:50PM
(#1415636)
Yes, you can't even turn them off by unplugging them, as it were. A certain kind of emergency shutdown dumps the helium needed to allow superconductivity (and thus maintain the magnetic field). It costs like $20,000 to do this and is quite dangerous in itself.
[ Parent
| on HN ]
Yeah, I should have thought this through. I knew you kept them cool, and with a bit of thinking it should have been clear that you don't turn a superconducting coil off, since nothing's powering it... ;-)
It's called MRI quenching and dangerous it can be[1].
Re:Metal chair near MRI machine
by InclinedPlane on Wednesday June 09, 2010 @02:04AM
(#1416304)
Modern high-field superconducting MRI magnets can hold tens of megajoules of stored magnetic field energy, equivalent to the explosive energy in several kilograms of TNT.