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Old 20-September-2008, 02:56 PM
grant hutchison grant hutchison is online now
Order of Kilopi
 
Join Date: Jul 2005
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Quote:
Originally Posted by tdvance View Post
it's funny to call the "fire brigade" when the magnets heat up to less than 100 degrees (C) below (not absolute) 0. I assume the "by 100 degrees C" from, presumably, liquid-helium temperature, is not a misstatement, of course!
I'd guess not. The fire brigade have the necessary breathing apparatus and dangerous-materials handling skills. When you get even a moderate quench, from the helium coolant in a medical MRI scanner for instance, you quickly lose breathing air as the helium boils and rapidly displaces everything else.
I was once present during the commissioning of a new medical MRI, before the emergency ventilation was tested and working. There was a large temporary sign on the wall, reading "In case of helium quench, throw chair through window glass."

Grant Hutchison
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