Measurement of rubidium and xenon absolute polarization at high temperatures as a means of improved production of hyperpolarized Xe-129

We report on a rubidium-xenon (Rb-Xe) polarization unit for the continuous production of large quantities of hyperpolarized Xe-129. The unit includes two diagnostic systems which enable the absolute measurement of both the Rb -85 and Xe-129 polarization in situ and at high temperatures. The Rb diagno stic system allows the measurement of one- or two-dimensional images of the absolute Rb polarization and thus enables the experimental study of light penetration into the optical pumping cell. The equilibrium Xe polarization measured in the optical pumping cell and in the freezing unit is typically similar to 20%, under optimal flowing conditions, and this is much lower th an the volume-averaged rubidium polarization. Copyright (C) 2000 John Wiley & Sons, Ltd.