Instrumentation for the measurement of single-particle circular intensity differential scattering for bioaerosol detection

We report the development of a prototype that can measure the single-particle phase function of circular intensity differential scattering (CIDS), i.e., the angular scattering ratio distribution of the Mueller matrix element −S14/S11 from individual single particles drawn into the system from the atmosphere or an aerosol generator. The system is developed from a laboratory experimental setup, improved, and constructed into a portable prototype with a dimension of 24 ′ ′ ×18 ′ ′ ×12 ′ ′ for field measurements. The design facilitated the fast detection of bioaerosol particles or others with spiral/helical molecular structures at a size from 1 to 10 micron in diameter. The system achieved a maximum particle screening rate of 50,000 particles/sec.