Partially polarized 3-MeV neutrons have been scattered from ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ contained in a high-pressure gas scintillation cell. The resulting asymmetry in the elastic scattering was determined for seven scattering angles from 40 to 120° (lab). Time-of-flight techniques and neutron-$\gamma$-ray discrimination in the side detectors were used for background reduction. The measured asymmetry is small for angles less than 60° (lab) and reaches a maximum value at approximately 110° (c.m.). The maximum asymmetry determined from the present experiment corresponds to a polarization of +0.50. The differential polarization can be fitted within experimental uncertainties by assuming that $D$-wave effects are negligible. The principal features of the data are qualitatively reproduced by Dodder's reaction-matrix calculations which use the Werntz-Meyerhof level parameters for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$.

• Received 10 June 1971

DOI:https://doi.org/10.1103/PhysRevC.5.395