time constant, \(\tau_{\text{c}}\)

of a detector
If the output of a detector changes exponentially with time, the time required for it to change from its initial value by the fraction \(1 - \exp(-t/\tau _{\text{c}})\) (for \(t=\tau _{\text{c}}\)) of the final value, is called the time constant.
PAC, 1995, 67, 1745. (Nomenclature, symbols, units and their usage in spectrochemical analysis-XI. Detection of radiation (IUPAC Recommendations 1995)) on page 1751 [Terms] [Paper]