Hyperpolarization read-out through rapidly rotating fields in the zero- and low-field regime

Area of Science:

• Magnetic Resonance Spectroscopy
• Quantum Information Science
• Hyperpolarization Techniques

Background:

• Para-hydrogen induced polarization (PHIP) enhances NMR/MRI signal sensitivity.
• Efficient conversion of nuclear singlet order to observable magnetization is crucial for PHIP.
• Existing methods face limitations in heteronuclear polarization transfer and quadrupolar decoupling.

Purpose of the Study:

• To achieve polarization transfer to a heteronucleus using a novel approach.
• To investigate the influence of rotating magnetic fields and bias fields on polarization transfer.
• To explore the potential of the STORM technique for quadrupolar decoupled PHIP.

Main Methods:

• Utilized Singlet-Triplet Oscillations through Rotating Magnetic fields (STORM) pulse sequences.
• Employed a combination of a rotating magnetic field and a weak bias field (sub-μT).
• Experimentally validated the method using hyperpolarized (1-¹³C)fumarate.

Main Results:

• Efficient polarization transfer to heteronuclei was achieved via selective proton singlet-triplet state rotation.
• High rotation frequencies (kHz range) were found necessary for efficient STORM pulse operation.
• The direction of the rotating field significantly impacts polarization transfer efficiency.

Conclusions:

• STORM enables efficient polarization transfer in PHIP, exceeding typical zero- to ultralow field frequencies.
• The STORM procedure offers a promising route for quadrupolar decoupled polarization transfer.
• This technique advances the capabilities of hyperpolarization methods for various applications.