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Romalis, M. V.; Miron, E.; Cates, G. D.

doi:10.1103/physreva.56.4569

Cited by 188 publications

(131 citation statements)

References 42 publications

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“…where we've assumed pumping with perfectly monochromatic light with frequency ν. Measurements by Romalis et al [20] and more recently by Lancor et al [31][32][33] indicate that |T d | is of order 0.1 ps for alkali-3 He collisions. Using this value, we find that (3σ 3 .…”

Section: The Alkali X-factorsmentioning

confidence: 93%

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Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

et al. 2015

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We present the development of high-performance polarized 3 He targets for use in electron scattering experiments that utilize the technique of alkali-hybrid spin-exchange optical pumping. We include data obtained during the characterization of 24 separate target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. The results presented here document dramatic improvement in the performance of polarized 3 He targets, as well as the target properties and operating parameters that made those improvements possible. Included in our measurements were determinations of the so-called X-factors that quantify a temperature-dependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable 3 He polarization to well under 100%. The presence of this spinrelaxation mechanism was clearly evident in our data. We also present results from a simulation of the alkali-hydrid spin-exchange optical pumping process that was developed to provide guidance in the design of these targets. Good agreement with actual performance was obtained by including details such as off-resonant optical pumping. Now benchmarked against experimental data, the simulation is useful for the design of future targets. Included in our results is a measurement of the K-3 He spin-exchange rate coefficient k K se = (7.46 ± 0.62)×10 −20 cm 3 /s over the temperature range 503 K to 563 K.

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Section: The Alkali X-factorsmentioning

confidence: 93%

“…Using existing accurate measurements of the pressure broadening of Rb absorption lines [20], it was possible to monitor the pressure of the sealed target cells at the level of roughly 1%. These data also provided a measurement of D by comparing the integral of the absorption lines of the two different alkali species.…”

Section: Determining the 3 He Densitymentioning

confidence: 99%

Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

et al. 2015

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“…The presence of nitrogen is required in the gas mixture for quenching the fluorescence of the excited alkali vapor atoms [4]. Natural helium ( 4 He) is also commonly used as a buffer gas to increase the overall pressure inside the cell in order to take advantage of the pressure broadening effects on the Rb D1 absorption line [23].…”

Section: Introductionmentioning

confidence: 99%

Large Production System for Hyperpolarized 129Xe for Human Lung Imaging Studies

et al. 2008

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“…Relaxation due to persistent dimers can be suppressed at high B 0 field [9], however this is not always practicable. The dependence of σ(ν) on gas density has been extensively studied by Romalis et al [10]. For a gas mixture of 3% Xe, 10% N 2 , 87% He, the absorption width (FWHM) at 70…”

Section: Hyperpolarisedmentioning

confidence: 99%

Enhancement of X129e polarization by off-resonant spin exchange optical pumping

Parnell

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Parra‐Robles

et al. 2010

Journal of Applied Physics

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A high power narrow line width (38W, 0.09nm FWHM) external cavity diode laser is investigated for rubidium spin exchange optical pumping of 129 Xe. This tunable photon source has a constant line width, independent of operating power or wavelength within a 1 nm tuning range. When using this laser, an increase in the 129 Xe nuclear polarisation is observed when optically pumping at a lower wavelength than the measured Rb electron D 1 absorption. The exact detuning from D 1 for the highest polarisation is dependent upon the gas density. Furthermore, at high power and/or high Rb density, a reduction of the polarisation occurs at the optimum wavelength as previously reported in SEOP studies of 3 He which is consistent with high absorption close to the cell front face. These results are encouraging for moderate high throughput polarisation of 129 Xe in the mid pressure range of (0.5-2.0 amg). * Electronic address: S.R.Parnell@Sheffield.ac.uk † Electronic address: J.M. Wild@Sheffield.ac.uk

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Pressure broadening of RbD1andD2lines by

Cited by 188 publications

References 42 publications

Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

Development of high-performance alkali-hybrid polarizedHe3targets for electron scattering

Large Production System for Hyperpolarized 129Xe for Human Lung Imaging Studies

Enhancement of X129e polarization by off-resonant spin exchange optical pumping

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