Neutron Cross Sections at 120 and 345 Ev

Abstract

Total neutron cross sections of 19 elements have been measured at 120 and 345 ev by employing the neutron resonance scattering properties of cobalt and manganese. Thin foils of cobalt and manganese were used as neutron detectors at 120 and 345 ev, respectively. A semilogarithmic plot of neutron counts versus thickness of sample was made for each element for each of the two energies. An initial curvature in the plot indicated that the detector resonance overlapped a resonance in the element under study. The cross section determined from either a straight-line plot or the asymptotic part of a transmission curve was identified as either the potential scattering cross section, the off-resonance scattering cross section, or as the minimum cross section in the neighborhood of a resonance.