Total Cross Section forn−pScattering at 20 Mev

Abstract

The total scattering cross section for neutrons incident on protons has been measured in a good-geometry transmission experiment. The scatterer was hydrogen gas contained in a pressure vessel one meter long, at a pressure of 4000 psi. The resulting cross section is o-*=0.4942±0.0025 barn at a laboratory neutron energy of 19.665±0.026 Mev. 3 The transmission cell was designed and tested in 1951 by Mills, Edeskuty, and Sesonsky of this Laboratory, at the request of J. H. Coon. A description of the cell appears in J. D. Seagrave and R. L. Henkel, Phys. Rev. 98, 666 (1955), Appendix I. 4 Coon, Bondelid, and Phillips [quoted in Coon, Graves, and Barschall, Phys. Rev. 88, 562 (1952)] used the same cell for an accurate hydrogen total cross-section measurement at 14 Mev. 209