Spin-exchange collisions and their consequences for spin-polarized gas targets of hydrogen and deuterium

Abstract

The effects of spin-exchange collisions on the polarization of dense spin-polarized samples of hydrogen and deuterium are analyzed. It is shown that even in large magnetic fields spin-exchange collisions transfer angular momentum between the electrons and the nuclei. This effect has important implications for the operation of densed spin-polarized targets and sources of hydrogen and deuterium. For tensor polarized targets care will be required to obtain a high tensor polarization, especially at low fields. For the specific case of sources that are spin-polarized by spin-exchange collisions with optically pumped alkali atoms, spin-exchange not only polarizes the hydrogen and deuterium electron spins, but polarizes the nuclear spins as well. For high-density vector-polarized targets this may eliminate the need for rf transitions to polarize the nuclei.