Surface-Collision Analysis of Microscale-Confined ¹²⁹Xe in Pyrex Vapor Cells Based on Stem-Transport and Gradient...

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Sensing
• Materials Science

Background:

• Surface collisions at Pyrex walls in nuclear magnetic resonance gyroscopes (NMRG) limit spin coherence.
• Cavity-stem junction geometry influences ¹²⁹Xe atom transverse spin relaxation time (T2).

Purpose of the Study:

• To decompose Xe atom relaxation by combining T2 measurements with Monte Carlo simulations.
• To derive a cavity-stem geometry correction for wall relaxation.
• To introduce a structural coupling factor (SCF) for predicting transverse relaxation rate versus geometry.

Main Methods:

• Utilized T2 measurements and Monte Carlo simulations of confined diffusion and surface collisions.
• Developed a structural coupling factor (SCF) to quantify diffusion-limited mixing.
• Validated the model against eight simulated configurations, achieving R²=0.982.

Main Results:

• The model accurately predicts experimental results within 7-9% agreement.
• Geometry optimization reduced the relaxation rate by 41.8% (from 0.225 to 0.131 s^-1).
• The developed framework accounts for cavity-stem coupling effects on relaxation.

Conclusions:

• The Pyrex surface-collisional analysis offers an in-situ, T2-based method for evaluating surface depolarization.
• This approach allows for comparison of fabrication and surface-treatment protocols.
• The study provides a pathway to optimize NMRG performance by minimizing relaxation rates through geometric adjustments.