Modern magnets are available with shielding of the external magnetic field. This is achieved by use of a second superconducting coil which compensates the magnetic field outside the magnet. Bruker’s Ultrashield Technology drastically reduces the stray field to close to the magnet and thus strongly reduces the magnetic field to which the operator is exposed. All Bruker USR magnets include refrigeration technology for long helium hold time and minimum number of maintenance intervals.
Our USR magnets utilize the latest pulse tube cryo-cooler technology to improve cryogenic efficiency and at the same time minimize the transfer of unwanted vibration to the magnet system. This is essential in order to achieve optimum artefact-free performance without the vibration related problems associated with other active refrigeration methods. This is possible because pulse tube coolers are far superior to earlier technologies in that they do not employ moving pistons and therefore feature quiet operation with no mechanical wear and tear to the cold components.
The USR magnet systems also combine traditional thermal shield cooling well known in clinical MRI magnets with a patented technique of recondensing the gaseous Helium. This combination results in outstanding cooling efficiency.