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



Thomas R. Gentile, T G. Walker, E Babcock, Qiang NMN Ye, Wangchun Chen


Using diode bar lasers spectrally narrowed with chirped volume holographic gratings (VHGs), we have obtained an improvement in the 3He polarization achievable by spin-exchange optical pumping (SEOP). As compared to our past results with lasers narrowed with diffraction gratings, we have observed between 5 % and 11 % fractional increase in the 3He polarization. These results were primarily observed in large cells but we also report higher polarization in small cells, in particular one flat-windowed cell in which prior extensive studies indicated that the alkali-metal polarization was within 3 % of unity. We conclude that the most likely explanation for the improvement in 3He polarization is increased alkali-metal polarization, which has impact on understanding the maximum 3He polarization achievable by SEOP. The maximum polarization we have observed is P_ He=0.85 in a neutron spin filter cell nearly 1 liter in volume.
Physical Review A


He3, laser, optical pumping


Gentile, T. , Walker, T. , Babcock, E. , , Q. and Chen, W. (2014), On the limits of spin-exchange optical pumping of 3He, Physical Review A, [online], (Accessed April 23, 2024)
Created July 2, 2014, Updated November 10, 2018