ANALYZING POWER IN NEUTRON-DEUTERON ELASTIC-SCATTERING AT E(LAB)N=3 MEV

A measurement of the analyzing power A(y)(theta) in neutron-deuteron ( n-d) elastic scattering below the deuteron breakup threshold is descri bed, including a detailed discussion of the experimental apparatus and the treatment of systematic errors. The data provide a precise test o f Faddeev calculations of the three-nucleon system and of the nucleon- nucleon interaction models used as inputs to these calculations. A(y) was measured at six angles from 44.5-degrees c.m. to 145.7-degrees c.m . to a precision of (7-13) x 10(-4). Polarized neutrons, produced by t he H-3(p over arrow pointing right, n over arrow pointing right)He-3 r eaction, were incident upon the target, a deuterated organic scintilla tor. Scattered neutrons were detected in fast coincidence with the rec oil deuterons in the target. A computer simulation of the experiment w as used to compensate for a number of systematic errors. Particularly important were corrections for neutron multiple scattering, accidental coincidences, and finite geometry effects. The A(y) data have a 2.2% scale factor uncertainty associated with uncertainty in the polarizati on of the incident neutron beam. The incident neutron polarization was measured in a separate experiment using n-He-4 scattering from a liqu id helium scintillator. The neutron polarization measurement also yiel ded an improved value for the polarization transfer coefficient [K(y)y (0-degrees) = 0.650+/-0.019] in the H-3(p over arrow pointing right, n over arrow pointing right)He-3 reaction at E(lab)p = 3.80 MeV. A comp arison of the A(y) data to Faddeev calculations shows that the discrep ancy in A(y) observed previously at higher energies continues below th e breakup threshold. A comparison of the A(gamma) data to a recent pha se shift analysis of proton-deuteron (p-d) scattering indicates that o bserved differences between n-d and p-d analyzing powers are only part ially explained by Coulomb effects.