Presented here is the application of an adjoint technique for solving source-detector discrete ordinates (S_N) transport problems by using a spectral nodal method. For slab-geometry adjoint S_N model, the adjoint spectral Green’s function method (SGF^†) is extended to multigroup problems considering arbitrary L′th order of scattering anisotropy, and the possibility of nonzero prescribed boundary conditions for the forward S_N transport problem. The SGF^† method converges numerical solutions that are completely free from spatial truncation errors. In order to generate numerical solutions of the SGF^† equations, we use the partial adjoint one-region block inversion (RBI) iterative scheme. Partial adjoint RBI scheme uses the most recent estimates for the region-edge adjoint angular fluxes in the outgoing directions of a given region, to solve the resulting adjoint S_N problem in that region for all the adjoint angular fluxes in the incoming directions, which constitute the outgoing adjoint angular fluxes for the adjacent region in the sweeping direction. Numerical results are given to illustrate the present spectral nodal method’s features and some advantages of using the adjoint technique in source-detector problems.

此处介绍的是一种伴随技术的应用，该技术通过使用频谱节点方法来解决源探测器离散纵坐标（S _N）传输问题。对于平板几何伴随S _N模型，考虑频谱L阶的任意各向异性，伴随光谱格林函数函数（SGF ^†）扩展到多组问题，以及正向S _N传输问题的非零规定边界条件的可能性。SGF ^†方法收敛了完全没有空间截断误差的数值解。为了生成SGF的数值解^†方程，我们使用部分伴随一区块反演（RBI）迭代方案。部分伴随RBI方案使用给定区域出射方向上的区域边缘伴随角通量的最新估计，以解决该区域中传入方向上所有伴随角通量的结果伴随S _N问题，在扫描方向上相邻区域的输出伴随角通量。数值结果说明了当前的谱节点法的特点以及在源-探测器问题中使用伴随技术的一些优点。