Scattering of 1.32-Mev Neutrons by Protons

The total cross sections of polyethylene and graphite for scattering of neutrons of 1.315±0.003 Mev have been measured and are $\sigma \left(\mathrm{C}{\mathrm{H}}_2\right)=(9.542\mathrm{}\pm 0.035)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^2$ and $\sigma \left(\mathrm{C}\right)=(2.192\mathrm{}\pm 0.020)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^2$. From these the hydrogen cross section is $\sigma \left(\mathrm{H}\right)=(3.675\mathrm{}\pm 0.020)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^2$. If the best current values of the binding energy of the deuteron (see [3]) the coherent scattering length (see [4]) and the epithermal cross section (see [5]) are used, the singlet effective range in the shape-independent approximation is (2.4±0.3)×${10}^{-13\mathrm{}}$ cm. This is to be compared with the proton-proton singlet effective range of (2.7±0.1)×${10}^{-13\mathrm{}}$ cm.