A dual-core NMR system for field-cycling singlet assisted diffusion NMR

Area of Science:

• Magnetic Resonance
• Materials Science
• Physical Chemistry

Background:

• Long-lived singlet spin order can significantly extend spin memory.
• This extended lifetime is beneficial for nuclear magnetic resonance (NMR) diffusion experiments in porous media.
• Internal field gradients from magnetic susceptibility inhomogeneities cause short T2 decay, limiting singlet order access in high fields.

Purpose of the Study:

• To develop a novel system for preparing and manipulating singlet spin order in porous media.
• To overcome limitations of high magnetic fields for singlet order experiments.
• To enable advanced NMR diffusion measurements, including diffusion tensor imaging.

Main Methods:

• Development of a dual-core system operating in field-cycling mode.
• Low-field preparation and manipulation of singlet order using radiofrequency and 3-axis pulsed field gradients.
• High-field probe for polarization and detection, enabling singlet-assisted diffusion experiments.

Main Results:

• Demonstration of a field-cycling system for singlet order preparation and detection.
• Successful application in NMR diffusion experiments, providing access to longer diffusion times (minutes).
• Immunity to internal field gradients, allowing exploration of tortuosity in porous structures.

Conclusions:

• The developed dual-core system effectively prepares and manipulates long-lived singlet spin order.
• This approach overcomes high-field limitations, enabling unprecedented insights into porous media.
• The system facilitates advanced NMR diffusion measurements, including singlet-assisted diffusion tensor imaging.