AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
The Splitter Bias Measurements for Calibration of Optical Particle Sizer (OPS) Using Wafer Surface Scanner (WSS) Method for 3 μm Particles at Ultra-Low Concentrations
SHIGERU KIMOTO, Lin Li, George Mulholland, Miles Owen, David Y. H. Pui, University of Minnesota
Abstract Number: 406 Working Group: Instrumentation and Methods
Abstract Optical particle counters (OPCs) are widely used to measure aerosol size distribution and number concentration in the size range of approximately 0.1 to 30 μm by means of light scattering from single particles. They are applied to low concentration measurements such as clean room or ambient PM monitoring, and to high concentration industrial aerosols, e.g. industrial filtration. There is interest in the accurate calibration of OPCs at low concentrations (10-1000 particles/L) of particles in the size range of 1-5 μm in terms of their use for measuring the concentration of virulent biological structures. For the U.S. military, there is interest in calibrating an Optical Particle Sizer (OPS) at low concentrations of 3 μm particles with traceability to SI units realized by the National Institute of Standards and Technology (NIST). This is in support of fielded and future biological agent detectors. Particles are collected on a silicon wafer in a deposition chamber via gravity, and counted by a wafer surface scanner (WSS). Methodology and experimental results at ultra-low concentrations of 10-100 particles/L (total deposited concentration is 100-800 particles/L) by OPS and WSS were reported by Li et al. in 2012. However, the splitter bias measurement was not enough.
In this study, we carried out the splitter bias measurement and calibration at the same concentrations ranging from 10-100 particles/L. The splitter bias measurements were carried out by test OPS, reference OPS and CPC. Then, test OPS was calibrated by three kinds of instruments (WSS, CPC and a reference OPS). We will report detail for this study.