Alternate functions to describe solar cell degradation

We have found that the empirical function described in the JPL Solar Cell Radiation Handbooks can describe the degradation of solar cell parameters for many solar cell technologies. In particular, when the degradation is presented in terms of displacement damage dose (D/sub d/), they permit a quantitative description of the response for protons over a wide energy range. Here we show that several of the distributions used in reliability and survival theory can successfully describe solar cell degradation. Possible advantages of using these functions and limitations of the empirical expression are also outlined.