Cryogenic superconducting magnet system for use in magnetic resonance apparatus, and controlling the temperature of a heat shield therein

摘要

A super conducting magnet system for magnetic resonance systems comprising at least one radiation shield. Temperature sensors, an external refrigeration system and a controller are provided for maintaining said at least one shield at a constant temperature by heating the shield and reducing the heat provided as the refrigerator system wears or by increasing the frequency of the refrigeration cycle as the system wears or both.