Low-AC-Loss Nb3Sn Validation Model Coil in Solid Nitrogen for a Fast-Switching-Field MRI Magnet Prototype

Area of Science:

• Superconducting magnet technology
• Magnetic Resonance Imaging (MRI) applications
• Advanced materials science

Background:

• Conventional MRI magnets utilize static magnetic fields.
• Rapidly switching magnetic fields in MRI offer potential for novel contrast mechanisms.
• Developing technologies for fast-field-switching superconducting magnets is crucial for next-generation MRI.

Purpose of the Study:

• To design and test a low-AC-loss Niobium-tin (Nb3Sn) model coil for a fast-switching-field MRI magnet.
• To validate enabling technologies for a magnet capable of switching between 3 T and 0.5 T within 1 second.
• To explore new contrast mechanisms like level-crossing and adiabatic demagnetization/remagnetization.

Main Methods:

• Development of a low-AC-loss Nb3Sn coil.
• Implementation of a novel cooling technology using heat-conductive thermal links to solid nitrogen.
• Anchoring thermal links to a cryocooler cold head for efficient heat transfer.
• Testing the model coil to analyze temperature rise during rapid field switching.

Main Results:

• Successful design and testing of the Nb3Sn model coil.
• Demonstration of a magnet design enabling rapid switching between high (3 T) and low (0.5 T) fields.
• Validation of a cooling system that prevents quench during fast field changes.
• Analysis of maximum temperature rise in the coil.

Conclusions:

• The developed low-AC-loss Nb3Sn coil and cooling system are key enabling technologies for fast-switching-field MRI magnets.
• This technology facilitates novel MRI contrast mechanisms and differential relaxometry.
• The design allows for rapid magnetic field changes without compromising superconducting stability.