On the limits of spin-exchange optical pumping of {sup 3}He
- University of Maryland, College Park, Maryland 20742 (United States)
- National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899 (United States)
- University of Wisconsin, Madison, Wisconsin 53706 (United States)
- Juelich Centre for Neutron Science at FRM 2, Forschungszentrum Juelich GmbH, 85747 Garching (Germany)
We have obtained improvement in the {sup 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 {sup 3}He polarization P{sub He}. We also report a comparable improvement in P{sub 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{sub 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{sub He} is increased alkali-metal polarization. We have observed P{sub He} of between 0.80 and 0.85 in several large cells, which marks a new precedent for the polarization achievable by SEOP.
- OSTI ID:
- 22306180
- Journal Information:
- Journal of Applied Physics, Vol. 116, Issue 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Recent Advances in Polarized He-3 Targets
First Use of Novel Techniques for Polarized He-3 Targets