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Measurement of spin-exchange rate constants between Xe 129 and alkali metals

2005; American Physical Society; Volume: 72; Issue: 2 Linguagem: Inglês

10.1103/physreva.72.022713

1538-4446

W. Shao, Guodong Wang, Emlyn Hughes,

Advanced MRI Techniques and Applications

By measuring the relaxation rates of the nuclear spin polarization of $^{129}\mathrm{Xe}$ in the presence of alkali-metal vapor at different densities, we have extracted the spin-exchange rates between $^{129}\mathrm{Xe}$ and the three alkali metals K, Rb, and Cs. By studying the alkali-metal--$^{129}\mathrm{Xe}$ spin-exchange rates as functions of the cell number density from 0.2 to 0.7 amagat, the binary collision and van der Waals molecular terms are separated, and constants governing both mechanisms are determined. The results from our work can be used to optimize the parameter space for polarizing $^{129}\mathrm{Xe}$, a promising agent for magnetic resonance imaging and other applications.