Abstract: Aspects of the present disclosure include a flow cell nozzle configured to propagate light emitted by a sample in a flow stream upstream by total internal reflectance. Flow cell nozzles according to certain embodiments include a nozzle chamber having a proximal end and a distal end and a nozzle orifice positioned at the distal end of the nozzle chamber where the flow cell nozzle is configured to propagate light emitted from a sample in the flow stream upstream through the flow cell nozzle orifice by total internal reflectance toward the proximal end of the nozzle chamber. Systems and methods employing the subject flow cell nozzles are also provided.

Abstract: The invention provides an apparatus and method for determining the position of a radiation beam. The apparatus includes (a) a first reflective surface and a second reflective surface, the reflective surfaces being placed to form the reflective exterior of a wedge; (b) a first detector placed to detect radiation reflected from the first reflective surface, and (c) a second detector placed to detect radiation reflected from the second reflective surface. The method includes the steps of (a) directing a radiation beam to the reflective exterior of a wedge formed by a first reflective surface and a second reflective surface; (b) selectively detecting radiation reflected from the first reflective surface; (c) selectively detecting radiation reflected from the second reflective surface; and (d) determining the position of the radiation beam based on the difference in the amount of radiation detected from each surface.

Abstract: The invention provides an apparatus and method for determining the position of a radiation beam. The apparatus includes (a) a first reflective surface and a second reflective surface, the reflective surfaces being placed to form the reflective exterior of a wedge; (b) a first detector placed to detect radiation reflected from the first reflective surface, and (c) a second detector placed to detect radiation reflected from the second reflective surface. The method includes the steps of (a) directing a radiation beam to the reflective exterior of a wedge formed by a first reflective surface and a second reflective surface; (b) selectively detecting radiation reflected from the first reflective surface; (c) selectively detecting radiation reflected from the second reflective surface; and (d) determining the position of the radiation beam based on the difference in the amount of radiation detected from each surface.

Abstract: The invention provides an apparatus and method for determining the position of a radiation beam. The apparatus includes (a) a first reflective surface and a second reflective surface, the reflective surfaces being placed to form the reflective exterior of a wedge; (b) a first detector placed to detect radiation reflected from the first reflective surface, and (c) a second detector placed to detect radiation reflected from the second reflective surface. The method includes the steps of (a) directing a radiation beam to the reflective exterior of a wedge formed by a first reflective surface and a second reflective surface; (b) selectively detecting radiation reflected from the first reflective surface; (c) selectively detecting radiation reflected from the second reflective surface; and (d) determining the position of the radiation beam based on the difference in the amount of radiation detected from each surface.

Abstract: The invention provides an apparatus and method for determining the position of a radiation beam. The apparatus includes (a) a first reflective surface and a second reflective surface, the reflective surfaces being placed to form the reflective exterior of a wedge; (b) a first detector placed to detect radiation reflected from the first reflective surface, and (c) a second detector placed to detect radiation reflected from the second reflective surface. The method includes the steps of (a) directing a radiation beam to the reflective exterior of a wedge formed by a first reflective surface and a second reflective surface; (b) selectively detecting radiation reflected from the first reflective surface; (c) selectively detecting radiation reflected from the second reflective surface; and (d) determining the position of the radiation beam based on the difference in the amount of radiation detected from each surface.

Abstract: This invention provides a radiation directing device, consisting of a screen having a mirrored surface interrupted by one or more pin holes that pass through the screen, the pin holes having an elliptical shape. The invention further provides an apparatus for determining radiation beam alignment. The apparatus includes (a) a screen having a mirrored surface interrupted by one or more pin holes passing through the screen; and (b) a means for detecting radiation reflected by the mirrored surface, wherein the detecting means determines a position of a radiation beam relative to the pin hole.

Abstract: A scanning apparatus is provided to obtain automated, rapid and sensitive scanning of substrate fluorescence, optical density or phosphorescence. The scanner uses a constant path length optical train, which enables the combination of a moving beam for high speed scanning with phase-sensitive detection for noise reduction, comprising a light source, a scanning mirror to receive light from the light source and sweep it across a steering mirror, a steering mirror to receive light from the scanning mirror and reflect it to the substrate, whereby it is swept across the substrate along a scan arc, and a photodetector to receive emitted or scattered light from the substrate, wherein the optical path length from the light source to the photodetector is substantially constant throughout the sweep across the substrate. The optical train can further include a waveguide or mirror to collect emitted or scattered light from the substrate and direct it to the photodetector.

Abstract: A scanning apparatus is provided to obtain automated, rapid and sensitive scanning of substrate fluorescence, optical density or phosphorescence. The scanner uses a constant path length optical train, which enables the combination of a moving beam for high speed scanning with phase-sensitive detection for noise reduction, comprising a light source, a scanning mirror to receive light from the light source and sweep it across a steering mirror, a steering mirror to receive light from the scanning mirror and reflect it to the substrate, whereby it is swept across the substrate along a scan arc, and a photodetector to receive emitted or scattered light from the substrate, wherein the optical path length from the light source to the photodetector is substantially constant throughout the sweep across the substrate. The optical train can further include a waveguide or mirror to collect emitted or scattered light from the substrate and direct it to the photodetector.

Abstract: A disposable first tube (68) extends axially through, and is detachably connected to, an annular main body (10'). An input piezo electric element (38) is attached to a first end of the tubular main body (10'). A second, sensor piezo electric element (40) is attached to the opposite end of the main body (10'). A nozzle (20') having a nozzle passageway (110) and a discharge opening (112) is detachably secured to an outlet end of the first tube (68). A second tube (102) within the first tube (68) delivers a core liquid to the nozzle passageway (110). A sheath liquid is delivered through a space in the first tube (68) surrounding the second tube (102). The nozzle passageway (110) forms the core and sheath liquids into a small diameter jet stream. Electrical energy is delivered to the input piezo electric element (38), to vibrate the nozzle (20') and break the jet stream into droplets.

Abstract: A disposable first tube (68) extends axially through, and is detachably connected to, an annular main body (10'). An input piezo electric element (38) is attached to a first end of the tubular main body (10'). A second, sensor piezo electric element (40) is attached to the opposite end of the main body (10'). A nozzle (20') having a nozzle passageway (110) and a discharge opening (112) is detachably secured to an outlet end of the first tube (68). A second tube (102) within the first tube (68) delivers a core liquid to the nozzle passageway (110). A sheath liquid is delivered through a space in the first tube (68) surrounding the second tube (102). The nozzle passageway (110) forms the core and sheath liquids into a small diameter jet stream. Electrical energy is delivered to the input piezo electric element (38), to vibrate the nozzle (20') and break the jet stream into droplets.

Abstract: Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

Abstract: A digitally synchronized parallel pulse processing and data acquisition system for a flow cytometer has multiple parallel input channels with independent pulse digitization and FIFO storage buffer. A trigger circuit controls the pulse digitization on all channels. After an event has been stored in each FIFO, a bus controller moves the oldest entry from each FIFO buffer onto a common data bus. The trigger circuit generates an ID number for each FIFO entry, which is checked by an error detection circuit. The system has high speed and low error rate.

Abstract: A method for detection of DNA sequences. In the method, chromatin (comprising protein and DNA) is contacted with a cross-linking agent for the protein of the chromatin to provide a substantially rigid chromatin particle. The DNA of the chromatin particle is then subjected to treatment to cause a separation of the individual DNA strands into single stranded DNA. Preselected sequences of the single stranded DNA are then contacted with a complementary polynucleotide probe specific for the DNA sequence of interest. The polynucleotide probe is marked with a fluorescent label thereby labelling a target sequence of DNA in the chromatin particles. The fluorescently tagged DNA sequences are then detected by subjecting the polynucleotide probe to a suitable light source and detecting the light emitted by the fluorescent label so as to identify the preselected DNA sequence.

Abstract: Identification of algae in water samples is carried out with a flow cytometer having at least one high intensity light source to provide a light path such as a laser, means for passing the algae through the light path and a system of detectors arranged to measure chlorophyll fluorescence and at least two other parameters such as forward light scattering, perpendicular light scattering, backward light scattering, pulse length and/or shape of the scattered signals, fluorescence and pulse length and/or shape of the fluorscence signals. In order to separate the light output from the flow cytometer into components which can yield useful measurements, a system of partially reflecting mirrors and dichroic mirrors is used. Preferably, the high intensity light source is two independent lasers having parallel light paths one of which is separated in a UV range and the other in an all lines mode.