Transverse Spin Relaxation in Liquid ¹²⁹Xe in the Presence of Large Dipolar Fields

Using spin-echo NMR techniques we study the transverse spin relaxation of hyperpolarized liquid ¹²⁹Xe in a spherical cell. We observe an instability of the transverse magnetization due to dipolar fields produced by liquid ¹²⁹Xe, and find that imperfections in the Π pulses of the spin-echo sequence suppress this instability. A simple perturbative model of this effect is in good agreement with the data. We obtain a transverse spin relaxation time of 1300 sec in liquid ¹²⁹Xe, and discuss applications of hyperpolarized liquid ¹²⁹Xe as a sensitive magnetic gradiometer and for a permanent electric dipole moment search.