Superconducting magnets are electromagnets that are partially built from
superconducting materials and therefore reach much higher
magnetic field intensity.
The
coil windings of superconducting magnets are made of wires of a type 2
superconductor (mostly used is niobium-titanium - up to 15
Tesla the critical temperature is less then 10
Kelvin). These coils have no resistance when operated at temperatures near
absolute zero (-273.15°C, -459°F, 0 K).
Liquid
helium (4.2 K) is commonly used as a coolant (sometimes in addition with a
second cryogen liquid nitrogen as an intermediate thermal shield to reduce the boil-off rate of liquid
helium), which consequently conclude refilling (intervals: liquid
helium ~ 3 month, liquid nitrogen ~ 2 weeks). There are cryogen-free superconducting magnets with a closed-cycle refrigerating system at the horizon. Superconducting magnets typically exhibit field strengths of greater than 0.5 T, operate clinically up to 3 T, and have a horizontal field
orientation, which makes them prone to missile effects without significant
magnetic shielding.
See also
Quenching.
See also the related poll result: '
In 2010 your scanner will probably work with a field strength of'