3H+d⇌n+4He measurements and absolute neutron-polarization determination at 50 MeV

Abstract The reaction 3 H(d, n ) 4 He is used to produce 50 MeV polarized neutrons, which at Θ n = 29.7° lab are analyzed in the inverse reaction 4 He( n , d) 3 H. At Θ d )(deut) = 25° lab the two reactions are time reversed (or more specifically, reciprocal), corresponding to the same center-of-mass angles and energies, so that the neutron polarization, P , and the (inverse reaction) neutron- 4 He analyzing power, A , are equal. Thus the measured asymmetry e = P 2 and the absolute neutron polarization at 50 MeV is determined as P = 0.480±0.016. A ( Θ d ) and σ d ( Θ d ) are also measured.