0 degree polarization transfer in sup 2 H( rvec p , rvec n ) pp at 54 and 71 MeV

Results of measurements of the transverse polarization transfer coefficients {ital K}{sub {ital y}}{sup {ital y}{prime}}(0{degree}) for {sup 2}H({ital {rvec p}},{ital {rvec n}}){ital pp} at 54 and 71 MeV are presented. The magnitude and energy dependence of this parameter have been determined with sufficient precision (4%) to permit the use of this reaction as a source of nearly monoenergetic polarized neutrons in precise measurements. {ital K}{sub {ital y}}{sup {ital y}{prime}}(0{degree}) is found to have a significant dependence on excitation energy. The results at low excitation energy are in agreement with calculations in the impulse approximation using the nucleon-nucleon phase shifts obtained from the Bonn or Paris potentials. A substantial difference from the results obtained using the empirical phase shifts is found. Results of measurements of the longitudinal polarization transfer coefficient {ital K}{sub {ital z}}{sup {ital z}{prime}}(0{degree}) at 54 MeV are also presented.