Measurement of the spin-dependent part of the scattering amplitude of slow neutrons on 19F using a polarized beam and a polarized target

Using a polarized target of CaF₂, we have measured the spin-dependent part of the scattering amplitude of slow neutrons on ¹⁹F. A value β=a₊-a₋=-0.135±0.002 F was found, 10 times smaller than a recent theoretical estimate. A control experiment measuring β=a₊-a₋ for the proton by Bragg scattering on a single crystal of LiH yielded the correct value within experimental error.