Stability Test of a Pair of Conical Coils for Open-Bore MRI Magnet

To improve the openness of MRI scanners and reduce potential patient claustrophobia, a novel magnet concept with conical-shaped outermost main coils was investigated. This concept may also improve the coil stability because the Lorentz force acting on conical coils is mostly perpendicular to the coil/former interface, which may reduce friction-slip induced quench risk. A pair of conical superconducting coils has been tested to evaluate its stability. The test coil has 16° conical angle with a 50-cm diameter at the smaller diameter end. Both coils are supported by an aluminum former embracing coil OD surfaces. The pair of coils was ramped in a vertical Dewar with instrumentation measuring coil temperature, current, voltage, and strains. Two training quenches were observed at 74% and 81% Io/Ic before the coil current reached 100% of the short sample Ic value.