دسته: SuperKandactive

SuperKandactive
MRI superconducting magnets use a coil made of alloys such as niobium/titanium or niobium/tin surrounded by copper. These alloys have zero resistance to electric current when cooled to about 10°C (-265°C). The coil is kept with liquid helium below this temperature. The power supply on either side of a short heated part of the coil is connected and the flow to the coil gradually increases over several hours to reach the desired magnetic field. The flow in the coil closed loop flows for a long time without significant reduction. One resulting feature is that the magnetic field is always there.
Surrounding copper acts as an insulator at low temperatures compared to the zero resistance of the alloy. Copper also protects alloy coil against loss in case of magnet shutdown. If the helium level drops too low or if a large ferromagnetic object enters the magnet marginal field, it can be extinguished. The shutdown leads to the loss of supercondactive with a lot of heat generated by the rapid cryogen flow and welding, or liquid helium. The gas produced explosively and suddenly exits the room by a quince pipe or quince pipe. But sometimes it can enter the scanning room and have threatening consequences.
Tesla’s Super Condactive 1.5 magnets allow for high-performance brain imaging, superior MR and SNR spectroscopy, and/or improved time and spatial resolution. But on the other hand, magnets above 1.5 T have additional challenges caused by RF heating, and increased noise caused by RF sensitivity and penetration, among other things.