Polarization of Protons from theHe3(d, p)He4Reaction

The polarization of protons from the ${\mathrm{He}}^3(d, p){\mathrm{He}}^4$ reaction has been measured at eight laboratory angles between 20° and 140° for six deuteron energies from 3 to 12 MeV. The polarization was determined by scattering the protons from carbon. For all energies measured the polarization is positive at forward angles with a maximum near a laboratory angle of 30°. The polarization passes through zero in the vicinity of 60° and has a broad peak of negative polarization at back angles. At the forward maximum the polarization increases with bombarding energy from +0.10±0.03 at 3 MeV, to +0.76±0.03 at 10 MeV and +0.73±0.04 at 12 MeV. The broad minimum in the polarization at larger angles shows a similar energy dependence but the minimum also shifts to larger angles with increasing deuteron energy. The most negative value of the polarization ($P=-0.66\mathrm{}\pm 0.05$) was found at 120° and 8 MeV. The present measurements suggest that the ${\mathrm{He}}^3(d, p){\mathrm{He}}^4$ reaction may be a useful source of 23-29 MeV polarized protons. The results are compared with measurements of the neutron polarization in the mirror reaction $\mathrm{T}(d, n){\mathrm{He}}^4$. Some new information on the polarization in the scattering of protons from carbon has also been obtained.