High-density production of spin-polarized atomic hydrogen and deuterium

The electron polarization of hydrogen (H) and deuterium (D) atoms in a spin-exchange optical-pumping apparatus has been measured as a function of H (D) density and magnetic-field strength. The atomic density was varied between 4×${10}^{13}$ and 2.6×${10}^{14}$ atoms/${\mathrm{cm}}^3$ and the magnetic-field strength from 120 to 400 mT. The results suggest that the atoms approach spin-temperature equilibrium even though the magnetic fields are large compared to the critical fields of the atoms.