Abstract: A system and a method of detecting and characterizing a bacterial colony are presented in which the results are determined within about 48 hours. The bacterial colony is disposed on a substrate and placed between a laser and detector. Light from the laser impinges upon and is scattered by the bacterial colony. The forward scattered light is detected by an optical detector. The signal from the optical detector is analyzed by an analyzer and displayed or supplied to a storage medium for review. As different strains of bacteria possess unique forward scattering fingerprints, the particular strain may be identified.

Abstract: An ensemble scattering particle sizing system employing optical means and unique methodology which generates reliable data relative to particle concentration, size distribution and spatial distribution, including axial spatial distribution, for particles disposed in light transmitting medium gas with a given sample volume, means including a beam transmitter, a transform lens, an apertured image plane and a relay lens are strategically associated with a sample volume and detector means to produce the desired results.

Abstract: An intelligent laser diffraction particle sizing system is disclosed. A portion of the primary laser beam is directed by beam splitter into a calibration leg, modulated, and passed through a diffraction reticle. The known diffraction signature of the reticle is then recombined with the primary beam to pass through the particle field. Both the modulated calibration diffraction signature and the portion of the primary beam scattered by the particles are collected by the transform lens and detected at the back focal plane using an X-Y photodiode array. The detector array elements are grouped into variable geometry annular rings. The ring detectors are continuously centered around the beam using feedback from the X-Y position detector which monitors beam deflection.

Abstract: Two beams of electromagnetic radiation with symmetric radial intensity distributions are directed through space. A particle sampling volume is defined by those portions of the two beams within the field of view of one or more radiation sensitive detectors. The detectors respond to scattered radiation or fluorescence from particles passing through the beams in the sampling volume. The detector output for a single particle indicates two signal pulses corresponding to those times when the particle was in one of the beams. The speed of the particle in the plane perpendicular to the beams is determined from the transit time or width of the signal pulses, and the angle of the particle traverse in that plane determined from the time-of-flight between the signal pulses. The speed and angle thereby determine two velocity components in the perpendicular plane. Then the exact particle trajectory is specified by the angle and one point on the trajectory which is determined from relative magnitudes of the signal pulses.

Abstract: The present invention is an improved multiple ratio single particle counter. Intensities of scattered radiation are measured at more than two angles and ratios of these intensities are derived. These ratios are compared with calibration curves to determine an unambiguous measure of the particle parameter.