Algorithm And Influencing Factors Of Optical Particle Counter Particle Size Resolution

With the application of clean rooms, Optical Particle Counters (OPC), as a cleanroom measurement tool, get more and more attentions. In order to evaluate the cleanroom reliably, OPC and other monitoring equipment must meet international standards. Based on the various current standards of OPC, the paper presents a method to calculate the resolution of OPCs; Calculated the size resolution of the domestic OPC and analyzed what makes the resolution change. Given the lognormal distribution applications in aerosol science, the resolution calculation methods in lognormal model is discussed.According to the standard particle light scattering signal, the probability density distribution model of the counting particle can be shown. Using the "half" counting method to calculate the experimental and compare it with the theoretical calibration curve got by MiePlot. From the recorded signal distribution, the paper calculates the size resolution of OPC at home and abroad, and experimentally analysis the effects on size resolution of the large angle scattered light collection system, sensitive region and unlinear circuits.The paper gives a universal size resolution algorithm, and the resolution of the OPC homemade at0.5micron has been carried out. It has been verified to meet the ISO requirement that does not exceed15%. The resolution of lognormal model is similar to that of the normal model. It has shown that particle properties, optical structure and electrical systems will affect the particle counter response signals and the size resolution, which can provide a basis for the performance improvements of OPC, especially in size resolution. the paper also compared the error of particle size published in JJF-1190and the size resolution in ISO21501, to easy homemade OPC calibration using international standards.