Hyperpolarized xenon can be used by surface chemists . Normally , it is difficult to characterize surfaces using NMR , because signals from the surface of a sample will be overwhelmed by signals from the far @-@ more @-@ numerous atomic nuclei in the bulk . However , nuclear spins on solid surfaces can be selectively polarized , by transferring spin polarization to them from hyperpolarized xenon gas . This make the surface signals strong enough to measure , and distinguish them from bulk signals .