Frequency-selective laser optical pumping and spin exchange of cesium with129Xe and131Xe in a high magnetic field

Luo, J. L.; Mao, Xi‐an; Chen, J.; Wang, S.; Zhao, Mingxin; Fu, Liping; Zeng, Xianghua

doi:10.1007/bf03162088

Cited by 6 publications

(4 citation statements)

References 25 publications

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“…Finally, the general concepts of cryogen free hp noble gas production are by no means restricted to SEOP with rubidium. SEOP with cesium vapor [59], [71], [72] has recently been shown to increase the 129 Xe polarization significantly compared to SEOP with rubidium [29]. The benefits of cesium vapor SEOP at low gas pressures, in particular with 83 Kr, are still unexplored.…”

Section: Resultsmentioning

confidence: 99%

Pathway to Cryogen Free Production of Hyperpolarized Krypton-83 and Xenon-129

et al. 2012

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Hyperpolarized (hp) 129Xe and hp 83Kr for magnetic resonance imaging (MRI) are typically obtained through spin-exchange optical pumping (SEOP) in gas mixtures with dilute concentrations of the respective noble gas. The usage of dilute noble gases mixtures requires cryogenic gas separation after SEOP, a step that makes clinical and preclinical applications of hp 129Xe MRI cumbersome. For hp 83Kr MRI, cryogenic concentration is not practical due to depolarization that is caused by quadrupolar relaxation in the condensed phase. In this work, the concept of stopped flow SEOP with concentrated noble gas mixtures at low pressures was explored using a laser with 23.3 W of output power and 0.25 nm linewidth. For 129Xe SEOP without cryogenic separation, the highest obtained MR signal intensity from the hp xenon-nitrogen gas mixture was equivalent to that arising from 15.5±1.9% spin polarized 129Xe in pure xenon gas. The production rate of the hp gas mixture, measured at 298 K, was 1.8 cm3/min. For hp 83Kr, the equivalent of 4.4±0.5% spin polarization in pure krypton at a production rate of 2 cm3/min was produced. The general dependency of spin polarization upon gas pressure obtained in stopped flow SEOP is reported for various noble gas concentrations. Aspects of SEOP specific to the two noble gas isotopes are discussed and compared with current theoretical opinions. A non-linear pressure broadening of the Rb D1 transition was observed and taken into account for the qualitative description of the SEOP process.

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Section: Resultsmentioning

confidence: 99%

Pathway to Cryogen Free Production of Hyperpolarized Krypton-83 and Xenon-129

et al. 2012

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“…a limit of |P AM | = 1 for D 1 OP). Thus, significant 129 Xe polarization can still be achieved using Cs SEOP at the D 2 line [14]. Greater light absorption at the D 2 line caused by the twofold higher oscillator strength [27] gives rise to lower optimal cell temperature (T OPT ) values [24] when switching from D 1 to D 2 SEOP.…”

Section: A 129 Xe-cs Seop: D 1 Versus D 2 Excitationmentioning

confidence: 99%

“…Yet despite these anticipated advantages and considerable effort (e.g., Refs. [12,14,15]), improved results with Cs have yet to be realized and Cs-129 Xe SEOP is still not widely practiced. Indeed, the development of Cs-129 Xe SEOP has been hindered by the lack of available high-power light sources that emit at the Cs D lines (equivalent to those available for Rb [8]), preventing the proper exploration of the SEOP parameter space [16]-and hence, limiting the xenon polarization that can be achieved.…”

Section: Introductionmentioning

confidence: 99%

Xe129-Cs (D1,D2<

et al. 2011

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We investigate 129 Xe-Cs (D 1 ,D 2 ) spin exchange optical pumping (SEOP) at high Xe densities (∼0.12-2.44 amagat) using newly available high-power (>40 W) laser diode arrays and compare with 129 Xe-Rb D 1 SEOP under similar conditions. At elevated Xe densities, the spin-exchange rate (per alkali-metal atom, γ ) for Cs-129 Xe is ∼1.5-fold greater than that for Rb-129 Xe. Higher spin-exchange rates and lower 129 Xe spin-destruction rates for Cs-129 Xe versus Rb-129 Xe contribute to ∼twofold improvement in 129 Xe nuclear spin polarization measured at 9.4 T-with the largest gains observed at the highest Xe densities.

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“…The fundamental details of hp 131 Xe production have been explored in some detail by Volk [29,54] , Happer [30–32] , Pines [33] , Mehring [34] , and their respective co-workers. Luo et al have also studied 131 Xe SEOP using cesium in high magnetic fields at 11.7 T [55] . Optically detected NMR experiments using SEOP were applied in the past to study the influence of the glass container surfaces on the gas-phase hp 131 Xe relaxation and were used to investigate xenon adsorption phenomena on glass surfaces [29–35] .…”

Section: Introductionmentioning

confidence: 99%

Hyperpolarized 131Xe NMR spectroscopy

Stupic

Cleveland

Pavlovskaya

et al. 2011

Journal of Magnetic Resonance

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Hyperpolarized (hp) 131Xe with up to 2.2% spin polarization (i.e., 5000-fold signal enhancement at 9.4 T) was obtained after separation from the rubidium vapor of the spin-exchange optical pumping (SEOP) process. The SEOP was applied for several minutes in a stopped-flow mode, and the fast, quadrupolar-driven T1 relaxation of this spin I = 3/2 noble gas isotope required a rapid subsequent rubidium removal and swift transfer into the high magnetic field region for NMR detection. Because of the xenon density dependent 131Xe quadrupolar relaxation in the gas phase, the SEOP polarization build-up exhibits an even more pronounced dependence on xenon partial pressure than that observed in 129Xe SEOP. 131Xe is the only stable noble gas isotope with a positive gyromagnetic ratio and shows therefore a different relative phase between hp signal and thermal signal compared to all other noble gases. The gas phase 131Xe NMR spectrum displays a surface and magnetic field dependent quadrupolar splitting that was found to have additional gas pressure and gas composition dependence. The splitting was reduced by the presence of water vapor that presumably influences xenon-surface interactions. The hp 131Xe spectrum shows differential line broadening, suggesting the presence of strong adsorption sites. Beyond hp 131Xe NMR spectroscopy studies, a general equation for the high temperature, thermal spin polarization, P, for spin I⩾1/2 nuclei is presented.

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Frequency-selective laser optical pumping and spin exchange of cesium with129Xe and131Xe in a high magnetic field

Cited by 6 publications

References 25 publications

Pathway to Cryogen Free Production of Hyperpolarized Krypton-83 and Xenon-129

Pathway to Cryogen Free Production of Hyperpolarized Krypton-83 and Xenon-129

Xe129-Cs (D1,D2<

Hyperpolarized 131Xe NMR spectroscopy

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