Hi, Iam reading the book Glen F. Knoll Radiation Detection and Measurements, and Iam having a trouble understanding a certain part of the chapter about semiconductor, he writes: Electron-hole pairs that are created within the depletion region by the passage of radiation will be swept out of the depletion region by the electric field, and their motion constitutes a basic electrical signal. The thermal generation of charge carriers will continue to take place in the depletion region, contributing a component sometimes called the generation current to the observed leakage current. These charges are swept away typically within a few nanoseconds, however, a time that is many orders of magnitude shorter than the time required to establish thermal equilibrium. Thus, the steady-state concentration of carriers is strongly reduced in the depletion region because the removal of charges is a much faster process than their creation. I dont understand the sentences in bold, why does it matter how fast they are swept away? As long as they are created, and move under an electric field, they constitute an electric signal. Sure, the depletion region is depleted of mobile charge carriers and that greatly reduces the leakage current, but this second benefit of the short time they are swept away? Iam certain that Iam missing something here. Can someone who understand this clarify this for me? Thank you very much!