Average energy expended per e-h pair for germanium-based dark matter experiments

We report a new method, which allows us to derive the temperature dependence of the average energy expended per electron-hole (e-h) pair, ε, for germanium detectors. Applying energy partition mechanism in ionization for a given energy deposition, the Fano factor and the value of ε can be determined separately. Subsequently, we illustrate the variation of ε as a function of temperature. The impact of ε on the energy threshold for germanium detectors at a given temperature is evaluated.