Laser Particle Counter Signal Simulation And Particle Size Resolution Optimization Based On Monte Carlo Method

Laser airborne particle counter(LAPC)is a kind of optic sensor playing an important role in monitoring the levitated particle.The particle size resolution is the most important parameter and is influenced by the scattering light collecting system a lot.This article introduced a theoretical model and discussed experiments of this system.Finally we provided a method to optimize LAPC and improve particle size resolution.This theoretical model contains Monte Carlo Tech and computed the results of four PSL standard particles based on Mie-Lorenz scattering theory.This scattering light collecting system is composed of PIN detector,photosensitive area,and reflector.Through finite element mesh method,the PIN detector and photosensitive area were divided into different parts.Then we did some research on spatial beam reflection coordinate transformation.As a result,scattering light intensity distribution and cumulative photon location distribution could be obtained.Meanwhile,we discussed about reasonability of the lognormal distribution model of noise model and accomplished the simulation software,ParticleCounter.We built an evaluation standard based on comentropy theory to test dispersion and discrimination.Lastly,we did some computation on circle reflector and ellipsoid reflector and searched for the best location of PIN detector.We did experiments on these two optimized LAPC and the original LM1612Ag LAPC according to the calibration rules and obtained the signal distribution results.This proved the accuracy of Monte Carlo random scattering model This optimized LAPC’s resolution is 92.6%,far beyond the nation standard 70%.Researches in this paper offered a new way to optimize LAPC and improve the resolution.