IN-SITU ULTRAFINE PARTICLE SIZING BY A COMBINATION OF PULSED-LASER HEATUP AND PARTICLE THERMAL EMISSION

A new in situ method for particle sizing is described. The aerosol par ticles are heated up by a laser pulse. Their thermal radiation is dete cted by a photomultiplier. Numerical analysis of the measured signal b ased on a solution of the first kind Fredholm integral equation result s in the particle size distribution. The method is characterized by me asurement time of less than some microseconds and applicable for measu ring particle size distribution in various Size ranges down to some na nometers. An example of the size distributions of soot particles measu red in a sooting propane diffusion flame is illustrated. Other possibl e applications of the method are discussed.