Patent ID: 6029458
Filing Date: 2000-02-29
Classification: G01R

Abstract:
A mechanical cryocooler cryogen recondensing zero-boiloff system utilizing a rare earth displacer for a magnetic resonance imager superconducting magnet comprising:a recondenser;said cryocooler thermally connected to said recondenser;a superconducting sleeve closely and partially surrounding said cryocooler rare earth displacer;said sleeve being magnetically coupled to the magnetic fields generated by the movement of said rare earth displacer to provide superconducting flow of currents induced in said shield by said magnetic fields;said superconducting magnet including a closed cavity to receive said cryocooler; andsaid sleeve is secured to said cryocooler for insertion therewith into said cavity and for removal therefrom;said superconducting flow of currents generating magnetic fields opposing said induced magnet fields to shield said superconducting magnet imaging volume from said magnetic fields generated by said movement of said rare earth displacer.