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arXiv · 0802.3169

Neutron Beam Effects on Spin Exchange Polarized He-3

M. Sharma·E. Babcock·K. H. Andersen·L. Barron-Palos·M. Becker·S. Boag·W. C. Chen·T. E. Chupp·A. Danagoulian·T. R. Gentile·A. Klein·S. Penttila·A. Petoukhov·T. Soldner·E. R. Tardiff·T. G. Walker·W. S. Wilburn
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Abstract

We have observed depolarization effects when high intensity cold neutron beams are incident on alkali-metal-spin-exchange polarized He-3 cells used as neutron spin filters. This was first observed as a reduction of the maximum attainable He-3 polarization and was attributed to a decrease of alkali-metal polarization, which led us to directly measure alkali-metal polarization and spin relaxation over a range of neutron fluxes at LANSCE and ILL. The data reveal a new alkali-metal spin-relaxation mechanism that approximately scales as the square root of the neutron capture-flux density incident on the cell. This is consistent with an effect proportional to the recombination-limited ion concentration, but is much larger than expected from earlier work.

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M. Sharma, E. Babcock, K. H. Andersen, L. Barron-Palos, M. Becker, S. Boag, W. C. Chen, T. E. Chupp, A. Danagoulian, T. R. Gentile, A. Klein, S. Penttila, A. Petoukhov, T. Soldner, E. R. Tardiff, T. G. Walker, W. S. Wilburn. 2008-02-21. Neutron Beam Effects on Spin Exchange Polarized He-3. https://doi.org/10.1103/physrevlett.101.083002

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