Relaxation of spin-polarized ${}^3\text{H}\text{e}$ in mixtures of ${}^3\text{H}\text{e}$ and ${}^4\text{H}\text{e}$ at about 330 mK

We report the measurements of depolarization probabilities of polarized ${}^3\text{H}\text{e}$ in a rectangular acrylic cell with a deuterated tetraphenyl butadiene-doped deuterated polystyrene coating filled with superfluid ${}^4\text{H}\text{e}$ at $\sim 330\text{mK}$ with a magnetic holding field of $\sim 7.3\text{G}$. We achieve a wall depolarization probability of $\sim 1.0\times {10}^{-7}$. Such a surface will find application in a new experiment searching for the neutron electric dipole moment and other applications.

Figure 1

(Color online) A schematic of the experimental setup.

Figure 2

${}^3\text{H}\text{e}$ longitudinal relaxation time versus temperature in a rectangular dTPB-dPS coated acrylic cell with a holding magnetic field of 7.3 G. The acrylic cell is filled with $\sim 0.89\text{mol}$ superfluid ${}^4\text{H}\text{e}$. The error bars are the quadrature sum of the statistical and systematic uncertainties. The figure inset shows the ${}^3\text{H}\text{e}$ $T_1$ as a function of the ${}^3\text{H}\text{e}$ molar concentration in superfluid ${}^4\text{H}\text{e}$ $\chi$ at $\sim 330\text{mK}$.

Figure 3

(Color online) (a) shows the ${}^3\text{H}\text{e}$ depolarization probabilities versus temperature in this work (black squares) with all ${}^3\text{H}\text{e}$ atoms in bulk superfluid ${}^4\text{H}\text{e}$. (a) also includes the derived DPs from [24] (blue circles), Fig. 3 in [5] (red triangles), Fig. 4 in [5] (green diamonds), and Fig. 1 in [6] (pink stars). All these data are obtained from open cell systems. (b) lists the derived DPs from sealed cells for comparison, including Fig. 2 in [4] (red triangles), Fig. 6 in [5] (green squares), Fig. 4 in [6] (black circles), Fig. 5 in [6] (blue stars), and Fig. 7 in [6] (pink open circles). In [4, 5, 6], ${}^3\text{H}\text{e}$ atoms are mostly in vapor phase.