In order to achieve the superconductivity in a magnet, the coil winding must be at extreme low temperature. Liquid Helium (4K) is for this purpose. For an MRI machine, what happens if you push the QUENCH button? This webpage ((http://mriquestions.com/what-is-a-quench.html)) states ” If the coil temperature rises above the superconductivity threshold (*Tc*), the winding suddenly develop a finite resistance. The several-dozen amperes of circulating current passing through this elevated coil resistance create heat. This heat causes a sudden, explosive boil-off of liquid helium. ”
Does this mean after pushing the QUENCH button, the coil temperature will rise? But how exactly pushing a button can make the coil temperature rise at the first place? It seems that the logic in this explanation in this webpage is: Push the QUENCH button -> coil temperature rises -> heat in the coil generates and increases -> liquid helium boils off.
But my understanding is that, after pushing the QUENCH button, the liquid helium will connect to room temperature in some way, such that liquid helium will boil off (becoming gas) and leave the coil winding container. At the same time, the temperature of coil winding itself rises, leading to the occurrence of a finite resistance. In this way, the magnet loses its superconductivity.
But I am not sure if my understanding is correct. I don’t know if it is true that pushing Quench button will first lead to liquid helium temperature rise. Even if it is true, I don’t know how. Could someone who knows this explain this like I am 5? Thank you very much!