Distillation of HDHD gas and measurement of spin–lattice relaxation times

The polarization (static or dynamic) of HD material requires very pure HD   samples, with H2H2 and D2D2 impurities concentrations smaller than 0.1%. A new distillation apparatus equipped with a mass spectrometer has been built. It allows reaching such a level of purity and also measurement of the H2H2 and D2D2 residual concentrations down to 0.05%. The NMR spin–lattice relaxation times T1H and T1D have also been measured. The apparatus is described as well as the distillation method. T1H and T1D data as a function of [H2][H2] and [D2][D2] concentrations are given, at 0.85 T and 1.8 K.