In-situ polarized 3 He-based neutron polarization analyzer for SNS magnetism reflectometer

We report here the construction and neutron transmission test results of an in-situ polarized 3 He-based neutron polarization analyzer system for the Magnetism Reflectometer at the Spallation Neutron Source, Oak Ridge National Laboratory. The analyzer uses the Spin-Exchange Optical Pumping method to polarize the 3 He nuclei of a cell of 3 He gas. Polarized neutrons scattered from the sample are intercepted by the polarized 3 He gas which strongly absorbs neutrons in one spin-state while allowing most neutrons in the other spin-state to pass through. To maintain a stable analyzing efficiency during an experiment, the 3 He gas is continuously polarized in - situ on the instrument. Neutron transmission measurements showed that 73% 3 He polarization was reached in this setup. © 2010, Insitute of Physics.

Keywords

Polarization, Magnetism, Neutron sources, Transmission, Measuring instruments, Optical pumping

Citation

Lee, W. T., Tong, X., Pierce, J., Fleenor, M., Ismaili, A., Robertson, J. L., Chen, W. C., Gentile, T. R., Hailemariam, A., Goyette, T. R., Parizzi, A., Lauter, V., Klose F., Kaiser, H., Lavelle, C., Baxter, D. V., Jones, G. L., Wexler J., & McCollum L. (2010). In-situ polarized 3 He-based neutron polarization analyzer for SNS magnetism reflectometer. Paper presented to the International Conference on Neutron Scattering 2009, 3th–7th May 2009. Knoxville, Tennessee, USA. In Journal of Physics: Conference Series, 251(1), 012086. doi:10.1088/1742-6596/251/1/012086