Sensors and methods for high-sensitivity optical particle counting and sizing

摘要

A method of compensating a single-particle optical sizing sensor for sizing particles in a relatively concentrated fluid suspension sample for turbidity of said suspension sample is described. The sensor operates on a light extinction principle whereby a photo-detector produces a signal V LE (t) having a baseline voltage level and a response to blockage of light by a particle as a downwardly extending pulse from said baseline voltage level. The method comprises passing a non-turbid suspension through said sensor, measuring a baseline voltage level V 0 produced in response to said non-turbid suspension, passing said relatively concentrated suspension sample through said sensor, measuring a baseline voltage V 0 T produced in response to said relatively concentrated suspension sample, calculating the ratio G = V 0 V 0 T , and adjusting said sensor in response to G to compensate for said turbidity when said relatively concentrated suspension sample passes through said sensor.