Calorimetric measurements of optical signals in electrostatic discharge studies

A method based on calorimetry and an instrument are described for the absolute measurement of the energy contained in optical radiation, especially in the optical signatures of electrostatic discharge. The optical emission of a spark gap, comprised of two stainless-steel spheres, was collected by an optical condenser system and focused on the calorimeter sensor. The system was calibrated using a set of light-emitting diodes and tested using either single-pulse discharge or a continuously operating optical source. The calorimeter system detectivity, in terms of output voltage related to the input energy, was determined to be 4.3 × 10⁷ V·J^-1 and its detection limit was 2.3 × 10^-13 J. The system has application for nonintrusive characterization of optical emissions associated with discharge events