10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Signal Detection for the Measurement of Aerosol Scattering Coefficients with an Integrating Nephelometer
HANS MOOSMULLER, Herbert Schloesser, Desert Research Institute
Abstract Number: 1365 Working Group: Instrumentation
Abstract Integrating nephelometers measure aerosol scattering coefficients integrated over most scattering angles (~4π) and generally detect and quantify the scattered light with photon-counting photomultipliers. Most commercial nephelometers use a background-subtraction scheme, measuring sequentially the scattering signal with the nephelometer light source turned on and the background signal with the light source turned off, and subtracting the background signal from the scattering signal. This scheme can be problematic for fast changing aerosol concentrations such as encountered in airborne applications near or in aerosol plumes. Such problems are exacerbated for multi-wavelength operation.
Here, we investigate different signal detection schemes for photon-counting nephelometers, including a detailed comparison of background-subtraction and Fourier-transform methods. Our signal analysis is based on the Poisson statistics of the photon-counting signal, simulating different detection schemes for single and multiple-wavelength nephelometers.