C code in which a list of temperature at a given position along the thickness of a medium are computed. The Monte Carlo algorithm solves the 1D steady state heat equation with a volumetric source terme corresponding to the **linearized** Radiative Transfer Equation in Intensity. Radiation occurs in emission/absorption and **diffusion**. The boundary conditions are Dirichlet ones, temperatures are imposed both on the left and right sides of the medium. Boundaries of the plate can be black or grey opaque surfaces (emissivity = 1 or != 1)