Dipolar and scalar 3He-129Xe frequency shifts in stemless cells

We study nuclear spin frequency shifts in a He-3-Xe-129 comagnetometer caused by spin polarization of He-3. 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 He-3 magnetization in the regime of fast spin diffusion. Using this control, we observe a scalar He-3-Xe-129 collisional frequency shift characterized by an enhancement factor kappa(HeXe) = -0.011 +/- 0.001, which is in excellent agreement with theoretical calculations.