AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Development of CPC Calibration Technique at Low Flow Rate
SHIGERU KIMOTO, George Mulholland, Miles Owen, David Y. H. Pui, University of Minnesota
Abstract Number: 643 Working Group: Instrumentation and Methods
Abstract Condensation particle counters (CPCs) are widely used to measure the number concentration by means of light scattering from single particles after growth by condensation. There is interest in a calibration method for low particle concentration . We previously developed a calibration method for the optical particle counter (OPC) at ultra-low concentration of 0.01-1 particle/cm3 using wafer surface scanning (WSS) technique for 3 µm PSL spheres. However, several issues limiting the accuracy of the previous measurements 1. Large flow rate uncertainty at the low flow of 0.1 L/min. 2. Large uncertainty in the sampling bias, 3. Possibility of particle losses in the diluter.
In this work, we developed a calibration methods for condensation particle counter (CPC) using WSS for four monodisperse PSL calibration spheres over the size range of 0.1 µm to 3 µm. We improved our calibration system by accurately measuring the flow using high sensitivity electronic manometers for the laminar flow elements, by extensively assessing the slitter bias, and by developing a new diluter to reduce the particle losses.