Polarized 3He Neutron Spin Filters at Oak Ridge National Laboratory

Jiang, Chenyang; Tong, Xin; Brown, Daniel R.; Lee, W.T.; Ambaye, Haile; Craig, J.W.; Crow, Lowell; Culbertson, Hugh M.; Goyette, R.; Graves-Brook, M.; Hagen, M.; Kadron, B.; Lauter, Valeria; McCollum, L.; Robertson, J. L.; Winn, Barry; Vandegrift, A.E.

doi:10.1016/j.phpro.2013.03.194

Cited by 22 publications

(12 citation statements)

References 12 publications

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“…The 3 He cell (named Phantom Lancer) used for these tests was made in house at the SNS. 12 The cell is 7 cm in diameter and 9 cm in length with a 3 He pressure of 1.5 bars. The relatively large diameter ensures full coverage of the incoming neutron beam.…”

Section: Test Resultsmentioning

confidence: 99%

Development of a compact in situ polarized 3He neutron spin filter at Oak Ridge National Laboratory

Jiang

Tong

Brown

et al. 2014

Review of Scientific Instruments

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We constructed a compact in situ polarized (3)He neutron spin filter based on spin-exchange optical pumping which is capable of continuous pumping of the (3)He gas while the system is in place in the neutron beam on an instrument. The compact size and light weight of the system simplifies its utilization on various neutron instruments. The system has been successfully tested as a neutron polarizer on the triple-axis spectrometer (HB3) and the hybrid spectrometer (HYSPEC) at Oak Ridge National Laboratory. Over 70% (3)He polarization was achieved and maintained during the test experiments. Over 90% neutron polarization and an average of 25% transmission for neutrons of 14.7 meV and 15 meV was also obtained.

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Section: Test Resultsmentioning

confidence: 99%

Development of a compact in situ polarized 3He neutron spin filter at Oak Ridge National Laboratory

Jiang

Tong

Brown

et al. 2014

Review of Scientific Instruments

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“…16 were used to clean the OPC. After thorough cleaning, the OPC was connected to the syringe through an indium seal.…”

Section: Tests and Resultsmentioning

confidence: 99%

“…The cleaning and baking process of the OPC is the same as described in Ref. 16. The only difference is that the glass-to-brass transition and the flange are not baked due to their low tolerance to heat.…”

Section: The Opc and The Seop Pumping Systemmentioning

confidence: 99%

Spin exchange optical pumping based polarized 3He filling station for the Hybrid Spectrometer at the Spallation Neutron Source

Jiang

Tong

Brown

et al. 2013

Review of Scientific Instruments

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The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60° horizontal and 15° vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized (3)He filling station based on the spin exchange optical pumping method. It is designed to supply polarized (3)He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the (3)He pressure with respect to the scattered neutron energies. The depolarized (3)He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

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“…Past reported results 10,22 primarily employed the NG6M cold neutron beam line. 33 More recent results for large spin filter (2), telescope lenses (3,4), steering mirrors (5a, 5b), cylindrical lens (6), spherical lens (7), polarizing beamsplitter cube for a horizontally polarized laser (8), diverging cylindrical lens (used when needed for long cells) (9), quarter-wave plate (10), and a side-pumped 3 He cell. cells routinely used for neutron scattering experiments were obtained on the Advanced Neutron Diffractometer/ Reflectometer (AND/R), 34 BT7 thermal triple-axis spectrometer, 35 the quasi-monochromatic NG3 SANS (small angle neutron scattering spectrometer), 36 and the new NG6A cold neutron beam line.…”

Section: Apparatusmentioning

confidence: 99%

On the limits of spin-exchange optical pumping of 3He

Chen

Gentile

et al. 2014

Journal of Applied Physics

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We have obtained improvement in the 3 He polarization achievable by spin-exchange optical pumping (SEOP). These results were primarily obtained in large neutron spin filter cells using diode bar lasers spectrally narrowed with chirped volume holographic gratings. As compared to our past results with lasers narrowed with diffraction gratings, we have observed between 5% and 11% fractional increase in the 3 He polarization P He . We also report a comparable improvement in P He for two small cells, for which we would not have expected an increase from improved laser performance. In particular, prior extensive studies had indicated that the alkali-metal polarization was within 3% of unity in one of these cells. These results have impact on understanding the maximum P He achievable by SEOP, whether the origin of the improvement is from increased alkali-metal polarization or decreased temperature-dependent relaxation. We conclude that the most likely explanation for the improvement in P He is increased alkali-metal polarization. We have observed P He of between 0.80 and 0.85 in several large cells, which marks a new precedent for the polarization achievable by SEOP. V C 2014 AIP Publishing LLC. [http://dx.

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Polarized 3He Neutron Spin Filters at Oak Ridge National Laboratory

Cited by 22 publications

References 12 publications

Development of a compact in situ polarized 3He neutron spin filter at Oak Ridge National Laboratory

Development of a compact in situ polarized 3He neutron spin filter at Oak Ridge National Laboratory

Spin exchange optical pumping based polarized 3He filling station for the Hybrid Spectrometer at the Spallation Neutron Source

On the limits of spin-exchange optical pumping of 3He

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