Cryocooler with a superconducting sleeve for a helium recondensing magnetic resonance imager

摘要

A cryogen recondensing magnetic resonance imager superconducting magnet utilizing a rare earth displacement material cryocooler (10) with a superconducting sleeve (20) surrounding a portion of the circumference of the cold end of the cryocooler to provide superconducting current flow of currents induced by movement of the rare earth displacer (14) to generate opposing magnetic fields which shield the imaging region of the superconducting magnet (30) from magnetic interference generated by movement of the cryocooler rare earth displacer. <IMAGE>