Airborne streaker sampling for PIXE analysis

Ground based aerosol sampling has inherent limitations for understanding atmospheric transport and dynamics. Sampling from aircraft platforms has limitations on the sampling time and quantity of aerosol mass that can be collected, especially if multiple samples per flight are required to allow for vertical or horizontal resolution. A modification of Florida State University circular streaker sampler has been made to enable aerosol samples to be collected isokinetically from a Lear jet. The samples are matched for analysis by PIXE or scanning electron microprobe. Features of the sampler include: a two stage isokinetic inlet matched to aircraft speeds of 550 km/h; remote computer control of the wing tip mounted sampler; up to twenty samples per flight on a single circular disk. Preliminary tests with the sampler are described, involving sampling of a coal fired power plant plume, and calibration of PIXE elemental concentrations against particle number density measured simultaneously with a forward scattering probe.