Calibration of a calorimeter for measurements of electrostatic discharge

Our study dealt with the factors that influence the accuracy of the measurements performed with a calorimeter, developed to detect the optical signal, emitted by the spark generated to facilitate experiments with electrostatic discharge. Experiments are described, which were performed with a special calorimeter and a compound optical source consisting of a spark gap, a human-body-model ESD signal generator, and four light emitting diodes. The spark gap was used as a versatile and more powerful source of optical emission than the human-body-model circuit; the LED source was used for calibration and alignment. For control, the spectrum of the spark discharge was measured with a spectrometer and a broadband photodetector. The calorimeter system sensitivity in terms of output voltage to input energy was reasonably linear, although its response depended somewhat on the gap separation. The long-term stability of the system was measured, and the system response was studied for threshold optical signals. The calorimeter was used to calibrate a spectrometer, that allowed the spark discharge to be measured in the visible and infrared regions. The optical signal collecting system was provided with a further calibration and alignment by means of a set of light emitting diodes. The calorimeter detectivity was D=4.3/spl times/10/sup 7/ V.J/sup -1/ and its detection limit 2.3/spl times/10/sup -13/ J. The system's response to the IEC standard human-body-model circuit was consistent with the measurements of the system's detectivity.