Detection of fast flying nanoparticles by light scattering over a large volume

Abstract

Detection of nanoparticles is of paramount importance for contamination control in ultra-clean systems. Light scattering is a well-known detection method which is applied in many different scientific and technology domains including atmospheric physics, environmental control, and biology. It allows contactless and remote detection of sub-micron size particles. However, methods for detecting a single fast moving particle smaller than 100 nm are lacking. In the present work we report a preliminary design study of an inline large area detector for nanoparticles larger than 50 nm which move with velocities up to 100 m/s. The detector design is based on light scattering using commercially available components. The presented design takes into account all challenges connected to the inline implementation of the scattering technique in the system: the need for the detector to have a large field of view to cover a volume with a footprint commensurate to an area of 100mm x 100mm, the necessity to sense nanoparticles transported at high velocity, and the requirement of large capture rate with a false detection as low as one false positive per week. The impact of all these stringent requirements on the expected sensitivity and performances of the device is analyzed by mean of a dedicated performance model.