The angular distribution of ${\mathrm{Li}}^6(n, \alpha ){\mathrm{H}}^3$ has been determined for 1.1, 1.5, and 2.0 Mev neutrons by track measurements in 100-micron Ilford $C2\mathrm{}$ and $E1\mathrm{}$ lithium-six loaded emulsions. The triton yield function has been expressed as a finite series of spherical harmonics in the center-of-mass system. The $s$ and $p$ components of the neutron wave appear to predominate in the reaction, but the data are not sufficiently accurate to exclude the possibility of contributions from higher angular momentum components.

The cross section was also determined for the reaction at neutron energies of 1.5 and 2.0 Mev relative to that at 0.60 Mev. This was done by exposing the same plate to 0.60-, and to 1.5- or 2.0-Mev neutrons; a long counter was used to measure the neutron flux at each energy. Tracks were selected in a suitable cone so as to resolve the two energy groups. Ther esults were 0.32±0.06 and 0.27±0.04 barn at 1.5 and 2.0 Mev, respectively.

• Received 29 March 1954

DOI:https://doi.org/10.1103/PhysRev.95.117