Adsorbed Xenon and the Brute Force Production of Hyperpolarized Xe-129
John R. Owers-Bradley, Eugeny Krjukov, and Jason O’Neill
School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
Hyperpolarized Xe-129 has numerous applications in magnetic resonance (NMR) and magnetic resonance
imaging. As an alternative to the laser optical pumping method of production of hyperpolarized Xe-129
gas, we have investigated the brute force technique which uses a very high magnetic field and millikelvin
temperatures. One obstacle to this technique is the extremely long spin lattice relaxation times of nuclei
in solids at very low temperature. We exploit the fact that liquid He-3 can be used as an effective relaxant
to enable Xe-129 to be spin polarized on a high surface area substrate (silica gel) in a few hours. We
are able to identify the contributions of different atomic layers to the magnetization by analyzing the
Xe-129 NMR spectrum. To use the polarized Xe-129, it must be removed from cryostat quickly before
depolarization. The He-3 relaxant evaporates at above 3K which helps but we find the addition of He4 at the lowest temperatures allows us to turn off the relaxation even earlier, thereby preserving the
the majority of the polarization as we warm up. The polarization technique could be applied to other
adsorbed species such as C-13 or P-31.
Sorting category: Ac Quantum gases, fluids and solids
Keywords: hyperpolarized, adsorbed gas, magnetic resonance, silica gel
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