Patent ID: 6864682
Filing Date: 2005-03-08
Classification: G01R

Abstract:
1. In a magnetic resonance tomography apparatus having a superconducting magnet that generates a basic magnetic field, a cryo-head disposed on a cryostat and operable through a plurality of successive piston cycles for cooling said superconducting magnet, and a gradient system that generates gradient magnetic fields, said cryo-head producing vibrations that vibrate said superconducting magnet and said gradient system and thereby produce disturbances in at least one of said basic magnetic field and said gradient magnetic fields, a method for compensating for said disturbances in at least one of said basic magnetic field and said gradient magnetic fields comprising the steps of: in a tune-up of said cryo-head operating said cryo-head through one of said piston cycles and determining at least one field term, selected from the group consisting of a zero order field term and a first order field term, in at least one of said basic magnetic field and said gradient fields, said at least one field term having a time curve associated therewith representing field disturbances caused by said vibrations of said cryo-head in said piston cycle; and during subsequent operation of said cryo-head, said superconducting and said gradient system, setting at least of a synthesizer frequency for operating said superconducting magnet, and gradient currents for operating said gradient system, dependent on said time curve to compensate for said disturbances.