Dipolar and scalar He3−Xe129 frequency shifts in stemless cells

Abstract

We study nuclear spin frequency shifts in a ${}^3\mathrm{He}\text{−}{}^{129}\mathrm{Xe}$ comagnetometer caused by spin polarization of ${}^3\mathrm{He}$. We use stemless cylindrical cells to systematically vary the cell geometry and separately measure the cell shape-dependent and shape-independent frequency shifts. We find that a certain aspect ratio for a cylindrical cell cancels the dipolar effects of ${}^3\mathrm{He}$ magnetization in the regime of fast spin diffusion. Using this control, we observe a scalar ${}^3\mathrm{He}\text{−}{}^{129}\mathrm{Xe}$ collisional frequency shift characterized by an enhancement factor ${\kappa }_{\text{HeXe}}=-0.011\pm 0.001$, which is in excellent agreement with theoretical calculations.