We have observed a linear pressure dependence of longitudinal relaxation time $T_1$ at 4.2 and 295 K in gaseous ${}^3\mathrm{He}$ cells made of either bare Pyrex glass or Cs- or Rb-coated Pyrex due to paramagnetic sites in the cell wall. The paramagnetic wall relaxation is previously thought to be independent of ${}^3\mathrm{He}$ pressure. We develop a model to interpret the observed wall relaxation by taking into account the diffusion process, and our model gives a good description of the data.

• Received 24 March 2011

DOI:https://doi.org/10.1103/PhysRevA.83.061401