Electroluminescence measured at different injection current densities is used to study the effect of particle irradiation on GaInP/GaInAs/Ge triple-junction solar cells. By employing the optoelectronic reciprocity relation, the irradiation-induced degradation in the J-V characteristics of all individual subcells and their underlying diode saturation parameters is derived. Also, the dependence of the solar cell irradiation response on the position of the irradiation-induced non-radiative recombination centers within the cell active region, i.e., the quasi-neutral regions and the space charge region, is discussed. (C) 2012 Elsevier B.V. All rights reserved.