On average for a Si crystal, 3.8 to 3.9 eV are dissipated per hole created. A bias placed across the crystal causes the electron-hole pairs to migrate and increases the conductivity of the crystal. The more holes created, the greater the increase in conductivity and the associated drop in resistance. The total charge conducted is directly proportional to the energy of the absorbed X-ray. Unlike a gas-flow detector there is no internal gain.
Detection is a statistical process and resolution is treated as for gas-flow detectors.
Resolution depends not only on the detector but also the electronics. Resolutions about 150 eV in EDS analysis. WDS systems can handle a much higher count rates without loss of resolution than EDS systems. Baseline conductivity due to thermal excitation of electrons from VB to CB in an imperfect crystal produces a leakage current and increased noise and backgrounds. In addition, as noted above, Li drifting is used to compensate for impurities.