Polarization of Protons from theHe3(d, p)He4Reaction

Abstract

The polarization of protons from the ${\mathrm{He}}^{3}(d, p){\mathrm{He}}^{4}$ reaction has been measured at eight laboratory angles between 20\ifmmode^\circ\else\textdegree\fi{} and 140\ifmmode^\circ\else\textdegree\fi{} 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\ifmmode^\circ\else\textdegree\fi{}. The polarization passes through zero in the vicinity of 60\ifmmode^\circ\else\textdegree\fi{} and has a broad peak of negative polarization at back angles. At the forward maximum the polarization increases with bombarding energy from +0.10\ifmmode\pm\else\textpm\fi{}0.03 at 3 MeV, to +0.76\ifmmode\pm\else\textpm\fi{}0.03 at 10 MeV and +0.73\ifmmode\pm\else\textpm\fi{}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 ($P=\ensuremath{-}0.66\ifmmode\pm\else\textpm\fi{}0.05$) was found at 120\ifmmode^\circ\else\textdegree\fi{} 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.