A simplified model of a solar particle receiver consisting in a single-layered, 1D dispersion of cold and spherical particles is investigated. An optimization is conducted to show the influence of the refractive index, the particle size and the volumetric fraction on the particle receiver reflectance. Different values of the main parameter are found as the best for minimizing the particle receiver reflectance, because various local minimums exist. Special attention is paid to large particles, which achieve small reflectance when appropriate choices of other parameters are made.