Prediction of solar cell degradation in space from the electron-proton equivalence

From a comparison between the degradation rates, induced by proton and electron irradiations, of the performances of GaAs quantum well based vertical cavity surface emitting laser, we deduce a coefficient of equivalence between the two types of irradiations. This coefficient allows us to calculate the fluence of protons of a given energy which produces the same degradation as a fluence of electrons of a standard energy. We apply the result of this analysis to the degradation of GaAs solar cells, demonstrating that this coefficient allows a quantitative prediction of the degradation induced by a proton irradiation, when the degradation induced by electrons at one energy is known.