SPARCLE is an in situ aerosol photometer capable of determining both the particle size and refractive index. These parameters are inferred from the angular distribution of light scattered by a particle. To measure the angular distribution, two light detectors are used. The main role of the first detector is to detect the event of a particle transiting in the scattering volume. Once an event is detected, the second detector is triggered to measure the angular distribution. The calibration of SPARCLE was done by measuring light scattered by a spherical particle with known diameter and refractive index.

In this project, the particle used is polystyrene latex bead with mean-size of 2 µm and refractive index of 1.59. The calibration indicates that the particle size and refractive index of a spherical particle can be retrieved based on the measured angular distribution.