If the output of a detector changes exponentially with time, the time required for it to change from its initial value by the fraction
(for
)
of the final value,
is called the time constant.
Source:
PAC, 1995, 67, 1745
(Nomenclature, symbols, units and their usage in spectrochemical analysis-XI. Detection of radiation (IUPAC Recommendations 1995))
on page 1751
