Patent ID: 6061132
Filing Date: 2000-05-09
Classification: G01N

Abstract:
A dual detector array with noise cancellation for a particle counter, comprising:a view volume having a fluid flowing therethrough, the fluid carrying particles, with a light source having a beam directed through the view volume;a pair of optical collection systems arranged transversely to the beam to collect light scattered by particles carried by the fluid flowing through the view volume, the optical collection systems opposing each other;first and second detector arrays, each array receiving light propagating from a different one of the optical collection systems and including a plurality of detectors, each detector providing an electrical output that can include both light fluctuating noise and particle signals indicative of sensed light scattered by particles within a predetermined sensing region, different sets of corresponding detectors in the first detector array and the second detector array sensing different common areas of the sensing region; andan output circuit receiving and processing preassigned groups of electrical outputs of the first and second detector arrays, the preassigned groups of outputs of the circuit being established to substantially reduce the likelihood that the processing of the outputs representing corresponding sets of detectors sensing the common areas of the sensing region cancels concurrent particle signals indicative of sensed light scattered by particles within the common areas of the sensing region so that the processing removes most of the light fluctuating noise from the particle signals to increase their signal-to-noise ratios.