| 摘要 |
<p>A cylindrical superconducting magnet system for magnetic resonance imaging comprises primary superconducting coils 30 within a vacuum vessel 14, a gradient coil assembly 22 axially aligned with and located radially within the primary superconducting coils, a gradient coil assembly support 24 radially positioned outside the primary superconducting coils and attached to the gradient coil assembly by mechanical attachments 26, which may pass through holes 40 in the vacuum vessel 14. At least some of the mechanical attachments comprise an active force transducer 45 arranged to provide impulses of force onto a surface of the gradient coil assembly to oppose vibrations of the gradient coil assembly. The active force transducers are located outside the vacuum vessel. They may be pneumatic, hydraulic or piezoelectric actuators, controlled by measurements or simulations of gradient coil vibration. The active force transducers cancel or eliminate gradient coil vibrations, thus reducing noise, eddy currents and heating.</p> |
