Uncertainty evaluation method of the scattering matrix measurements for the polarized scanning nephelometer

The polarized scanning nephelometer (PSN) is an instrument for measuring the multiangle scattering matrix of aerosol particles. Prior to being used, its measurement accuracy should be first verified. However, due to the complexity of the errors involved, it is very difficult to evaluate the measurement accuracy of the instrument reasonably, which limits the application of the PSN. In this work, taking di-ethyl-hexyl-sebacate droplets as an example, an uncertainty evaluation method of the scattering matrix measurements for the PSN is proposed. According to the measurement characteristics, the sources of uncertainty are divided into systematic effects and random effects. The corresponding evaluation method is then proposed for these two uncertainty categories, and the uncertainty introduced by systematic effects is investigated in depth via the Monte Carlo method. The evaluation results clearly show the variation trend of each uncertainty component as a function of the scattering angle in different matrix elements. The combined uncertainty is calculated and analyzed, and the result shows that the measurement uncertainty of the instrument is less than 0.0185, which verifies the accuracy of the instrument. This method can provide a reference for the accuracy evaluation of similar instruments.