Focusing of Aerosols into a Particle Beam at Pressures from 10 to 150 Torr

The study of aerosols including chemical analysis has been substan tially advanced after the development of aerodynamic focusing lenses. Test results of 2 such lenses are presented; 1 operating at pressures between 15 and 80 Torr and the other at higher pressures between 30 and 175 Torr. The lenses consist of 7 single orifices separated by spacers and contained in a tube of about 10 cm in length. Orifice diameters range from 1.40 to .25 mm, while the exit holes (nozzles) are smaller. Laminar gas flow within a lens produces a narrow particle beam which is directed into a vacuum chamber for analysis of beam width and position, aerosol transport efficiency, linearity, and other parameters. The lenses were tested both with spherical monodisperse oil particles (.34-4 mu m diameter) as well as nonspherical solid NaCl particles (.19-.85 mu m) simulating larger particles with lower density. Both lenses produce narrow aerosol beams with diameters smaller than 4 mm about 90 mm downstream of the nozzle. Although non...