Abstract
The slow neutron cross sections of free atoms of O, N, and A have been determined to be; O:3.73, N:9.96, A:0.68 barn. Between 1 and 15 ev the curve shows an slope of 0.34 barn× per atom. Measurements on these elements have been extended to over 10,000 ev with no resonances observed. Dependence of cross section upon neutron energy from 1 ev to 0.003 ev is presented for , , , O, methane, ethane, propane, -butane, cetane, ethylene, 1,3-butadiene, and liquid-butane. At the lowest energies, the large observed cross section is attributed largely to thermal translational motion of the molecule. The measurements on the hydrocarbons show the effect of the binding of H in various molecules. Comparison with the theories of Bethe and Arley is made. No difference has been detected in cross-section measurements on gaseous and liquid -butane.
- Received 19 August 1949
DOI:https://doi.org/10.1103/PhysRev.76.1750
©1949 American Physical Society