Neutron Depolarization on Scattering from Carbon, Paraffin, and Phosphorus

The depolarization of polarized thermal neutrons scattered from carbon, paraffin, and phosphorus has been measured. The results have been interpreted in terms of the spin flip probability on scattering, which for carbon was found to be equal to -0.09±0.21 and for hydrogen 0.56±0.10, consistent with the theoretically expected values 0 and 0.65, respectively. For phosphorus, the measured spin flip probability of 0.73±0.15 yields an incoherent scattering cross section of 3.7±0.8b, of the same order of magnitude as the total scattering cross section (3.4b). This would imply one or more $s$-neutron resonance levels in phosphorus above 400 ev, the present upper limit of the well investigated part of the total neutron cross section of phosphorus.