Abstract: To locate/size contaminants at the surface of a dielectric or semiconductor material, a P-polarized beam of light from a monochromatic solid-state source is disposed specifically at Brewster's angle and focused to form an illuminated quasi-elliptical spot on the surface that produces effectively no reflected or scattered light from the surface. The spot is scanned over the entire surface so as to assure multiple passes of any contaminant through the spot. On each pass through the spot a contaminant will produce scattered light. A novel high numerical aperture reflective or refractive system is disposed above the surface to always view the spot and to collect/redirect the bulk of the contaminant scattered light to a detector. Illumination at Brewster's angle combined with the high numerical aperture scattered light collector/redirector maximizes the signal-to-noise ratio from the detector. These core components are packaged with support subsystems as a uniquely compact and portable apparatus.

Abstract: An airflow control valve for a clean room having a duct section with a damper positioned within the duct. The damper being capable of an adjustment from an open position to a closed position. The opening and closing of the duct is accomplished through a magnetic coupling such that the duct can remain sealed during operation. The airflow control valve includes a sensor for measuring the airflow rate, so that the duct can be adjusted to maintain one or more predetermined flow rate set-points.

Abstract: A device for measuring and automatically controlling the volumetric rate of air through an air handling system used in connection with clean rooms. A desired volumetric air rate is maintained by measuring air pressure differentials between different locations in the system. The volumetric air rate is adjusted by using a variable frequency drive to adjust the speed of the fan in response to a measured pressure differential.