Robust solid $^{129}$Xe longitudinal relaxation times

TL;DR

This study demonstrates that forming solid xenon as ice enhances the $^{129}$Xe longitudinal relaxation time and measurement reproducibility, with results aligning with SRRS theory but indicating a smaller coupling strength.

Contribution

It reveals that ice formation improves $^{129}$Xe relaxation times and reproducibility, providing new insights into spin-rotation interactions in solid xenon.

Findings

Ice formation increases $^{129}$Xe T1 by 10%.

Reproducibility of T1 measurements improves across 77-150 K.

No isotopic dependence observed in relaxation mechanisms.

Abstract

We find that if solid xenon is formed from liquid xenon, denoted "ice", there is a 10% increase of $^{129}$Xe longitudinal relaxation $T_1$ time (taken at 77 K and 2 Tesla) over a trickle-freeze formation, denoted "snow". Forming xenon ice also gives unprecedented reproducibility of $^{129}$Xe $T_1$ measurements across a range of 77-150 K. This temperature dependence roughly follows the theory of spin-rotation mediated by Raman scattering of harmonic phonons (SRRS), though it results in a smaller-than-predicted spin-rotation coupling strength $c_{K0}/h$. Enriched ice $^{129}$Xe $T_1$ experiments show no isotopic dependence in bulk relaxation mechanisms at 77 K and at kilogauss fields.