The total cross section of slow neutrons on gaseous orthodeuterium has been measured near 22 K and at pressures ranging from 145 to 300 Torr. The results give rise to a set of values for the neutron-deuteron scattering lengths that are in significant disagreement with the latest liquid mirror measurements. The relationship between the scattering lengths was found to be: ${(2\mathrm{}{a}_4+a_2)}^2+\left(\frac{5}{4}\right){(a_4-a_2)}^2=(2.313\mathrm{}\pm 0.003)\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^2$.

NUCLEAR REACTIONS ${}_{}{}^2{}_{}{}^{}\mathrm{H}(n, n)$; $E=4.2\mathrm{}$ meV; orthodeuterium; measured total neutron cross section; deduced relationship between $a_2$ and $a_4$.

• Received 29 April 1975

DOI:https://doi.org/10.1103/PhysRevC.12.1428