Compact 3He gas polarizers based on metastability-exchange optical pumping

Area of Science:

• Atomic, Molecular, and Optical Physics
• Nuclear Physics
• Materials Science

Background:

• High nuclear polarization of helium-3 (3He) is crucial for various applications, including medical imaging and fundamental physics research.
• Existing methods for polarizing 3He gas face limitations in speed, efficiency, and flexibility for delivering polarized gas to external systems.

Purpose of the Study:

• To design, construct, and operate novel polarizers capable of delivering highly nuclear-polarized 3He gas with enhanced flexibility.
• To investigate and model the key processes affecting the performance of 3He polarizing systems.

Main Methods:

• Utilized metastability-exchange optical pumping for rapid polarization of 3He nuclei at millibar pressures.
• Employed peristaltic compression to transfer optically polarized 3He gas to storage or experimental cells.
• Developed models incorporating gas flow, diffusion, and nuclear relaxation to analyze system performance.

Main Results:

• Demonstrated typical 3He gas polarization values (M) of 0.4-0.6.
• Achieved initial compression to over 600 mbar.
• Obtained flow rates up to 5 standard cubic centimeters per minute.

Conclusions:

• The developed polarizers offer a flexible and efficient method for producing and delivering highly nuclear-polarized 3He gas.
• The study provides insights into optimizing polarizer design by analyzing limiting factors like gas flow and relaxation.
• The demonstrated performance supports the utility of these systems for diverse applications requiring polarized 3He.