Effect of Inelastic Scattering on the Neutron Transmission by a Lead Single Crystal

The results of an experiment and calculations aimed at studying the transmission of monochromatic neutrons by a lead single crystal are presented. The temperature dependence of the total cross-section obtained in the experiment is well described by a calculation taking one-, two- and three-phonon neutron scattering into consideration. An additional temperature-independent component of the total neutron interaction cross-section has been found. It is assumed that this component is associated with the presence of a small number of impurity atoms, which strongly absorb neutrons, in the studied lead sample. It is shown that in the absence of a neutron-absorbing impurity in lead, a lead single crystal can be used as a gamma-radiation filter without a significant neutron loss.