Measurement And Study Of Photon Detector Performance Based On Spontaneous Parametric Down-Conversion

According to the development and application requirements of future space science, a design scheme of self-calibration broad spectrum radiation reference source based on spontaneous parametric down conversion is proposed. Photon detector is the core device of self-calibrating radiation source.Now the performance parameters of photon detectors mainly rely on factory data, but some parameters is not accuracy and may change as time goes on. it is necessary to calibrate the instrument because of needs of use.In the first part of paper, the international research status of parametric down-conversion effect is investigated and reviewed. Then an optical radiometric calibration setup is established using parametric down-conversion effect. A CW 355nm laser is used to pump a BBO crystal. The quantum efficiency of Avalanche Photo Diode is calibrated at 736nm based on time amplitude conversion coincidence measurement, the key factors which influence the quantum efficiency are analyzed, including time related character about coincidence, accidental coincidence counts, dark counts and transmittance of optics. The total relative uncertainty is less than0.7%.A linear measurement device was set up based on the linear relationship between pump power and photons in spontaneous parametric down conversion process. The nonlinearity errors mechanism, linear condition and correction model of photon counting detector were analyzed. For the sake of realizing the linear measurement of the photon counting, the pump power was adjusted to change incident photon rate, and the experimental measurements were corrected. The results show that the measurement precision can be improved by measurement and correction. The maximum linear range rate of the incident photon could be expanded from 105/s to 107/s result from lower non-linear errors.The afterpluse probability is measured with time amplitude conversion technique, which analyzes the statistical distribution of the photon counting pulse at a certain time interval. The APD’s afterpluse probability is about 1% and increases with the light intensity.The photon detector parameters of quantum efficiency, afterpulse and linear were analyzed in this paper, and the measuring method and results are discussed. In order to avoid the limitation application of time amplitude conversion,several coincidence count schemes are proposed in this paper,which may provide valuable reference for future development of photon count measurement.