Precision Measurement of the Total Neutron Cross Section ofU233between 0.000818 and 0.0818 ev

The absolute value of the total neutron cross section of ${\mathrm{U}}^{233}$ was measured at neutron energies between 0.000818 ev and 0.0818 ev for two types of samples, a metallic foil and ${\mathrm{D}}_2$O solutions of uranium nitrate. Balanced solutions of ${\mathrm{U}}^{233}$ ${\mathrm{O}}_2$ ${\left(\mathrm{N}{\mathrm{O}}_3\right)}_2$ and ${\mathrm{U}}^{238}$ ${\mathrm{O}}_2$ ${\left(\mathrm{N}{\mathrm{O}}_3\right)}_2$ were used to determine the difference between the total cross sections of ${\mathrm{U}}^{233}$ and ${\mathrm{U}}^{238}$. This value when combined with the relatively small known value of the total cross section for ${\mathrm{U}}^{238}$ gives ${\sigma }_T\left({\mathrm{U}}^{233}\right)=587\mathrm{}\pm 5$ barns at 0.0253 ev. The measurements on the metallic ${\mathrm{U}}^{233}$ foil agreed with the measured total cross section determined from the liquid solution data to better than 1%, yielding ${\sigma }_T\left({\mathrm{U}}^{233}\right)=586\mathrm{}\pm 2$ barns at 0.0253 ev.