METHOD AND APPARATUS TO INCREASE THE RESOLUTION AND WIDEN THE RANGE OF DIFFERENTIAL MOBILITY ANALYZERS (DMAS)

摘要

A differential mobility analyzer (DMA) for separating charged particles or ions suspended in a gas and a method of using the DMA for separating such particles. The invention includes various means for increasing the resolutio n of the DMA by stabilizing the laminar flow within the DMA and by allowing unusually large flow velocities. These means include several screens (2,3) o f high uniformity, a converging section (5), and a flow constriction leading t o a nozzle (8) that isolates the working region (13) from other regions furthe r downstream in order to avoid or reduce perturbations on the axisymmetry of steadiness of the flow in the working region (13).