Dead time correction in coincidence counting of photon pairs

Abstract

We describe two methods for evaluating the dead time of a time-to-amplitude converter (TAC). The dead time is obtained by measuring either the corresponding time interval in an oscilloscope trace or the relation between the single count rate and the coincidence count rate. Values for the TAC dead time are obtained in the range from 3.4 mu s to 14.3 mu s for the two methods with respective standard uncertainties of 2.9 x 10(-8) s and 3.3 x 10(-9) s. The TAC dead time is applied to the calibration of coincidence-counting measurements of optical transmission and photon-heralding efficiency.