POLARIZING NUCLEI IN SOLIDS VIA SPIN TRANSFER FROM AN OPTICALLY-PUMPED ALKALI VAPOR

摘要

The present invention relates to a method and system for polarizing a solid compound of interest via spin transfer from an optically-pumped alkali vapor. In one embodiment, the method provides a cell which contains a solid compound as well as pure alkali metal and some amount of buffer gas. The cell is heated to vaporize some of the pure alkali. Resonant laser light is passed through the cell to polarize the atomic vapor, a process known as "optical pumping." Optical pumping can transfer order from photons to atoms, causing a buildup of vapor atoms in one angular momentum state. This vapor polarization is then transferred through the surface of the solid compound in order to polarize the nuclei in the bulk of the compound. This can produce nuclear polarizations in the sample many times larger than the limit set by thermal equilibrium. The method can be used in nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI).