Answers are grounded in this paper and cite their sources.
The total neutron cross section of helium has been determined at energies from 40 kev to 4.9 Mev by comparison of the transmission of neutrons through a helium-filled cylinder with the transmission through an identical empty cylinder. The observed cross section increases smoothly from 0.8 barn at 40 kev to 6.7 barns at 1.15 Mev, and then decreases smoothly to 2.3 barns at 4.9 Mev. No splitting of the peak at 1.15 Mev was observed.
No takes yet. Share an insight, caveat, or question.
Bashkin et al. (1951) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: