MRI Magnets

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.

USR magnet systems exhibit a very compact shape and due to advanced coil design and elimination of the Nitrogen vessel, are considerably smaller than conventional magnets of the same field strength and bore size. Taken together with the very small stray field that results from advanced active-shielding, USR magnets fit more easily in a smaller room and have considerably less influence on other instruments nearby. They are of course very easy to transport and locate without much of the disruption experienced in installing conventionally designed systems. 

USR Magnet systems are extremely robust and designed to be shipped cold. This results in huge savings in both time and expense when installing and commissioning the system.

USR magnets are designed and built to operate at full efficiency without the need for a liquid Nitrogen vessel thereby completely eliminating the need for the regular liquid Nitrogen filling required by conventional systems. In addition, the outstanding thermal efficiency of the system results in an extremely low consumption of Helium requiring no intervention or maintenance by the user. The systems have a maintenance free period of more than twelve months between scheduled services to the refrigeration unit.