19 P 07 On-line measurement of particle size and composition

Abstract

The Particle Technology Group at Delft University of Technology is developing an instrument for on-line, real-time measurement of size and chemical composition of individual aerosol particles. Particles are sampled from an aerosol by using aerosol beam techniques. Collimated by the beam generator system the particles enter the ionization chamber of a time-of-flight mass spectrometer. There they are detected by the use of a photomultiplier when travelling through the beam of a small He-Ne laser and thereby scattering light. The photomultiplier signal is also used to trigger a Q-switched YAG laser which is vaporizing and ionizing the same particle. Analysis of the generated ions provides information on the chemical composition of the particles and the photomultiplier signal contains the particle size information.