In-situ Polarized<sup>3</sup>He-Based Neutron Polarization Analyzer for SNS Magnetism Reflectometer

Lee, W-T; Tong, Xin; Pierce, Jon L.; Fleenor, Michael; Ismaili, Akbar; Robertson, J. L.; Chen, Wangchun; Gentile, Thomas R.; Hailemariam, A.; Goyette, R.; Parizzi, A.; Lauter, Valeria; Klose, F.; Kaiser, H.; Lavelle, C. M.; Baxter, David V.; Jones, G. L.; Wexler, J.; McCollum, L.

doi:10.1088/1742-6596/251/1/012086

Cited by 7 publications

(9 citation statements)

References 5 publications

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“…The total laser power used in this system is 480 W with about 360 W delivered to the OPC. We have adopted the design from a SEOP system with the same level of laser power that can polarise 3 He at a fast rate [ 10 ]. However, a key difference of the system is the use of a rubidium cell rather than a “hybrid” rubidium‑potassium cell.…”

Section: Discussionmentioning

confidence: 99%

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Hyperpolarised gas filling station for medical imaging using polarised 129Xe and 3He

Lee

Zheng

Talbot

et al. 2021

Magnetic Resonance Imaging

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We report the design, construction, and initial tests of a hyperpolariser to produce polarised 129 Xe and 3 He gas for medical imaging of the lung. The hyperpolariser uses the Spin-Exchange Optical Pumping method to polarise the nuclear spins of the isotopic gas. Batch mode operation was chosen for the design to produce polarised 129 Xe and polarised 3 He. Two-side pumping, electrical heating and a piston to transfer the polarised gas were some of the implemented techniques that are not commonly used in hyperpolariser designs. We have carried out magnetic resonance imaging experiments demonstrating that the 3 He and 129 Xe polarisation reached were sufficient for imaging, in particular for in vivo lung imaging using 129 Xe. Further improvements to the hyperpolariser have also been discussed.

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Section: Discussionmentioning

confidence: 99%

“…In contrast, at least half-a-day is usually required to polarise 3 He. The shortest “pump-up” time-constant reported at the time was close to five hours [ 10 ], meaning that it would reach about 2/3 of the maximum polarisation in that time. Thus, polarised 3 He production would have a lower benefit from continuous-flow operation.…”

Section: Introductionmentioning

confidence: 99%

Hyperpolarised gas filling station for medical imaging using polarised 129Xe and 3He

Lee

Zheng

Talbot

et al. 2021

Magnetic Resonance Imaging

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“…13,14 An earlier prototype of this in situ system was described in detail previously 14,15 where a proof-of-principle experiment using the polarization analysis of four neutron spin-states was reported. 16 Those first experiments showed that for a timeof-flight experiment with high polarization efficiency and transmission, it is necessary to improve considerably the polarization of 3 He in order to use it for these kinds of experiments.…”

Section: The In Situ Pumping Systemmentioning

confidence: 99%

“…The front and back panels have 0.5 mm thick Si windows with dielectric coatings (to preserve laser light circular polarization) for the neutron beam to enter and exit. 14 During the operation, the system is controlled by a computer and is completely automated. We use NMR methods to monitor and control the polarization.…”

Section: The In Situ Pumping Systemmentioning

confidence: 99%

In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source

Tong

Jiang

Lauter

et al. 2012

Review of Scientific Instruments

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We report on the in situ polarized (3)He neutron polarization analyzer developed for the time-of-flight Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Using the spin exchange optical pumping method, we achieved a (3)He polarization of 76% ± 1% and maintained it for the entire three-day duration of the test experiment. Based on transmission measurements with unpolarized neutrons, we show that the average analyzing efficiency of the (3)He system is 98% for the neutron wavelength band of 2-5 Å. Using a highly polarized incident neutron beam produced by a supermirror bender polarizer, we obtained a flipping ratio of >100 with a transmission of 25% for polarized neutrons, averaged over the wavelength band of 2-5 Å. After the cell was depolarized for transmission measurements, it was reproducibly polarized and this performance was maintained for three weeks. A high quality polarization analysis experiment was performed on a reference sample of Fe/Cr multilayer with strong spin-flip off-specular scattering. Using a combination of the position sensitive detector, time-of-flight method, and the excellent parameters of the (3)He cell, the polarization analysis of the two-dimensional maps of reflected, refracted, and off-specular scattered intensity above and below the horizon were obtained, simultaneously.

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“…Several such SEOP based polarizer have been constructed for NSF [1,8,9,10]A block diagram of our device is shown in Figure 1. Additionally, diagnostics such as a free induction decay system to monitor 3 He polarization independent of neutrons and pump light absorption can be installed to aid in system monitoring and optimization.…”

Section: In-situ Seop Polarizermentioning

confidence: 99%

High level of 3He polarization maintained in an on-beam 3He spin filter using SEOP

Babcock

Mattauch

Ioffe

2011

Nuclear Instruments and Methods in Physics Research Section A:

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Maintaining high levels of 3 He polarization over long periods of time is important to many areas of fundamental and particle beam physics. Long measurement times are often required in such experiments and the data quality is a function of the 3 He polarization. This is the case for neutron scattering where the 3 He can be used to analyze the spin of a scattered neutron beam and relatively small fluxes of polarized neutrons leads to experiment times longer than several days. Consequently the Jülich Centre for Neutron Science (JCNS) is developing spin-exchange optical pumping (SEOP) systems capable of polarizing the 3 He gas in place on a typical neutron instrument. Using a polarizer device we constructed a high level of 3 He polarization of 81 % ±2 %was maintained with good time stability. Such levels of polarization maintained over time will be able to reduce the measurement times for such experiments and eliminate time dependent data corrections.

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In-situ Polarized³He-Based Neutron Polarization Analyzer for SNS Magnetism Reflectometer

Cited by 7 publications

References 5 publications

Hyperpolarised gas filling station for medical imaging using polarised 129Xe and 3He

Hyperpolarised gas filling station for medical imaging using polarised 129Xe and 3He

In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source

High level of 3He polarization maintained in an on-beam 3He spin filter using SEOP

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In-situ Polarized3He-Based Neutron Polarization Analyzer for SNS Magnetism Reflectometer

Cited by 7 publications

References 5 publications

Hyperpolarised gas filling station for medical imaging using polarised 129Xe and 3He

Hyperpolarised gas filling station for medical imaging using polarised 129Xe and 3He

In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source

High level of 3He polarization maintained in an on-beam 3He spin filter using SEOP

Contact Info

Product

Resources

About

In-situ Polarized³He-Based Neutron Polarization Analyzer for SNS Magnetism Reflectometer