TOTAL PARTICLE MONITORING AND DETECTION

ABSTRACT One of the methods of detecting particles in the ultrafine size range (diameter <0.05 μm) is by condensation nuclei counters. Such condensation nuclei counters have a broad range of application including clean room monitoring, the characterization of contaminants in fossil energy process streams, and atmospheric monitoring. Based on the condensation of a saturated vapor, the method can amplify the size of the particles which are being studied by several orders of magnitude so that they can be detected by standard optical methods. However, the lower size limit of detectability is dependent on the proper choice of parameters that create the saturation conditions. This paper presents results of the counting sensitivity tests of two condensation-type counters (the Pollak and the Sinclair continuous-flow counters). The results indicate that these instruments should be operated close to the self-nucleation limit in order to ensure total particle counting.