New results in the external Milne problem in cylindrical symmetry. Part 2. Two-group approximation

The asymptotic flux and the extrapolation distances are calculated in the two-group cylindrical Milne problem. The methods are based on the recent results in the elementary solutions approach in the two-group theory in plane geometry, and on the classical perturbational and variational procedures. As in part 1 for large and small R, the extrapolation distances are given in the form of asymptotic expansions. For intermediate values of R a version of the variational method especially adopted for the two-group theory is applied. For two examples (both for x=1) numerical results are presented. The convergence and the comparison confirm that sufficient accuracy is achieved. (author)