In recent months, experiments investigating the total, non-elastic, transport, etc., cross-sections of U-238 have been performed. It is the purpose of this memo to examine these data and to obtain from them information which will be of use in refinements pile calculations. In cases, e.g. transport cross-sections, where experimental data do not suffice, the theory developed pertaining to the continuum model of the nucleus has been depended upon. One of the fundamental requirements of this model is that the spacings of the energy levels in the compound nucleus are small compared to their widths and that consequently many levels are excited by the incoming particles. As a result there are many more modes of decay and the continuum model is an average over these levels.

The method of spherical harmonic tensors developed Mark for solving the Boltzmann transport equation in isotropic media is herein extended to anisotropic media for cylindrical geometry. A formal solution is given for the case of two concentric cylindrical media, A and B, but no numerical work has yet been done. The following treatment differs from a similar one by the H. K. Ferguson Co. in that the external medium B is assumed to be both a neutron absorber and finite in extent rather than a non-absorber and infinite in extent.