Temperature dependence of 3He polarization in aluminum storage cells

The temperature dependence of the polarization of 3He atoms in an internal target cell has been studied. Metastable optically pumped polarized 3He atoms with typical polarization values of 40% were injected into a thin-walled aluminum cell of 40 cm length and a 29.0 × 9.8 mm2 elliptical cross-section. The cell temperature was varied between 5 and 85 K. The polarization inside the target cell was measured via an asymmetry in the 3He→(d,p)4He reaction at a deuteron energy of 4 MeV. An exponential decrease of the polarization was found for temperatures less than 15 K. For a temperature of ∼6 K a polarization consistent with zero was measured.