Spherical Harmonic Solutions of the Neutron Transport Equation from Discrete Ordinate Codes

A method for obtaining spherical harmonic or P_L solutions of the transport equation from discrete ordinate or S_Ncodes is developed in this paper. This method depends on a new interpretation of the method as a projection method. The technique of converting S_Nsolutions into spherical harmonic solutions is discussed in detail for x-y geometry, and numerical results are presented. The method of this paper differs from earlier methods in that S_N solutions can be converted to P_N-1 solutions.