A study has been made of the ${\mathrm{Li}}^6(n, dn){\mathrm{He}}^4$ and ${\mathrm{Li}}^7(n, tn){\mathrm{He}}^4$ reactions over the energy region 5 to 14 Mev. The cross sections are very large and, as a consequence, normal Li may have important applications as a shielding material for fission and fusion reactors.

• Received 29 December 1961

DOI:https://doi.org/10.1103/PhysRev.126.1150