Prof. Haiyan Gao's graduate student, Wangzhi Zheng, has co-published a paper in Physical Review A as a Rapid Communication. Physical Review A is a publication on atomic, molecular, and optical physics. Read the abstract at the Physical Review A website here. Zheng submitted an introduction to the paper, which we've shared below.
From Wangzhi Zheng: Optically polarized Helium-3 gas has been widely used in many applications, such as neutron spin filter, signal source in nuclear magnetic resonance or magnetic resonance imaging, due to its ultra-high non-equilibrium polarization state. As the polarized Helium-3 gas has to inevitable relax back to its equilibrium state, which has negligibly small polarization, it is crucial to slow down the relaxation process so that a sizeable polarization can be maintained throughout the applications. Many mechanisms contribute to the relaxation, among which the most important one is the wall relaxation due to paramagnetic impurities embedded in the container surface. It is been widely accepted for more than half a century that the paramagnetic wall relaxation is independent of gas density. However, our recent experiment indicates that gas density plays an important role in the wall relaxation and the relaxation time has a linear dependence on the gas density. Further study shows that this linear dependence can be understood by incorporating the gas diffusion process into the wall relaxation mechanism. This new finding will guide researchers to lengthen the wall relaxation time, one of the main goals in the polarized noble gas community. This work is published on June 16, 2011 in Physical Review A as a rapid communication in Volume 83 » Issue 6, Phys. Rev. A {\bf 83}, 061401 (R) (2001).
Department of Physics
