Optically Pumped Atoms

Happer, W.; Jau, Yuan‐Yu; Walker, Thad

doi:10.1002/9783527629503

Cited by 147 publications

(182 citation statements)

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“…As a result, this simulation includes (1) the full solution to the coupled alkali-hybrid polarization equations, (2) the effect of off-resonant absorption by the Rb D2 & K Dn lines with realistic absorption lineshapes, (3) radiation trapping, which is included "by hand" by using the factors X a & X a , (4) skew optical pumping [27], and (5) effects associated with nonzero excited state populations. The role of each of these effects, which until recently [28,29] have not been included in most optical pumping simulations, can be understood by generalizing Eqn. (28):…”

Section: The Alkali X-factorsmentioning

confidence: 99%

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: 99%

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

et al. 2015

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“…For generating a strong nuclear spin polarization through collisions with polarized alkali atoms, 21 a pump laser beam is aligned along the z-axis. When superposing an oscillating magnetic field B x on the x-axis, the nucleus will be forced to precess in a coherent phase, and produce a magnetization projection in the x-y plane.…”

Section: Principlementioning

confidence: 99%

Effects of the pulse-driven magnetic field detuning on the calibration of coil constants while using noble gases

et al. 2018

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In the calibration of coil constants using the Free Induction Decay (FID) signal of noble gases, we analyse the effects of the pulse-driven magnetic field detuning on the calibration results. This method is based on the inverse relation between the π/2 pulse duration and its amplitude. We confirmed that obtaining a precise frequency is a prerequisite for ensuring the accuracy of research using the initial amplitude of the FID signal. In this paper, the spin dynamics of noble gases and its time-domain solution under the driving pulse have been discussed with regard to different detuning ranges. Experimental results are in good agreement with our theoretical predictions, which indicate the correctness of our theoretical deduction. Therefore, the frequency of the pulse-driven magnetic field is an important factor to the calibration of coil constants, it should be determined with a high degree of accuracy.

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“…All temperature-and pressure-dependent parameters used in the numerical analysis can be found in the literature [16][17][18][19][20] and are summarized in Table I. The details of the OPAM module shown in Fig.…”

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confidence: 99%

A plateau in the sensitivity of a compact optically pumped atomic magnetometer

et al. 2014

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In a compact optically pumped atomic magnetometer (OPAM), there is a plateau in the sensitivity where the dependence of the sensitivity on pumping power is small compared with that predicted by the uniform polarization model. The mechanism that generates this plateau was explained by numerical analysis. The distribution of spin polarization in the alkali metal cell of an OPAM was modeled using the Bloch equation incorporating a diffusion term and an equation for the attenuation of the pump beam. The model was well-fitted to the experimental results for a module with a cubic cell with 20 mm sides and pump and probe beams with 8 mm diameter. On the plateau, strong magnetic response was generated at the regions that were not illuminated directly by the intense pump beam, while at the same time spin polarization as large as 0.5 was maintained due to diffusion of the spin-polarized atoms. Thus, the sensitivity of the magnetometer monitored with a probe beam decreases only slightly with increasing pump beam intensity because the spin polarization under an intense pump beam is saturated. This plateau, which is characteristic of this type of magnetometer using a narrow pump and probe beams, can be used in arrays of magnetometers because it enables stable operation with little sensitivity fluctuation from changes in pump beam power.

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Optically Pumped Atoms

Cited by 147 publications

References 0 publications

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

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

Effects of the pulse-driven magnetic field detuning on the calibration of coil constants while using noble gases

A plateau in the sensitivity of a compact optically pumped atomic magnetometer

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