Abstract: A photometer readhead is used to measure concentrations within a test sample of preselected color-developed analytes having different characteristic absorption bands. The photometer readhead comprises an artificial light source for illuminating the test sample, a plurality of light-emitting diodes for detecting light transmitted through or reflected from the test sample, and a housing assembly for enclosing and supporting the plurality of light-emitting diodes. The plurality of light-emitting diodes have spectral responses encompassing respective ones of the different characteristic absorption bands of the preselected color-developed analytes.

Abstract: The high spatial resolution area array detection readhead and method for using the same involve modifying an existing area array detection readhead to provide improved spatial resolution within the sample detection area. One modification involves reducing the field of view of the area array detection readhead. The reduction in the field of view increases pixel spatial resolution because the same number of pixels in the area array detector cover a smaller area. This reduction can be achieved by changing the magnification of the lens of the area array detection readhead or by moving the sample detection area closer to the area array detection readhead. The next modification involves properly aligning the reduced field of view within the sample detection area to take advantage of the improved pixel resolution.

Abstract: A dual function readhead for a reflectance instrument is located in a housing for the instrument. A first light source for emitting radiation for reflectance readings and transmitting data is mounted in the readhead. In addition, a first photodetector is mounted in the readhead for detecting or receiving reflectance readings. A format or interface access port is defined in the readhead. An interface is provided that includes a second photodetector for detecting data transmitted by the first light source. A microprocessor is also provided for decoding data received by the second photodetector. A second light source may also be included with the interface for transmitting commands or data to the first photodetector. Software for controlling the operation of the first light source and the first photodetector is also provided.

Abstract: A dual beam spectrometer for conducting both turbidimetric and colormetric measurements includes a housing with a light source. The housing further includes source exit apertures that form light from the light source into a sample light beam and reference light beam. A sample cartridge for containing sample material to be measured is mounted in the housing in the path of the sample light beam. The spectrometer also includes a detector assembly for detecting the sample light beam and the reference light beam. The detector assembly includes a first detector that senses or detects sample light beam and a second detector that senses or detects the reference light beam. A sample light beam detection aperture tube is positioned in the housing between the sample cartridge and the first detector. Similarly, a reference light beam detection aperture tube is positioned between the sample cartridge and the second detector.

Abstract: An optical transmission spectrometer for transmission measurements of absorbing and scattering samples includes light sources mounted parallel to each other in a holder. The beams of light emanating from the light sources are directed through a beam-combiner. The beam-combiner includes a first refractive surface at an angle of incidence of 45.degree.. The first refractive surface refracts light toward a common axis. The beam-combiner includes a second refractive surface parallel to the first refractive surface for refracting the beam of light along a common axis parallel to the original direction of the beam of light. The beam-combiner can include additional refractive surfaces for other beams of light to combine the beams of light into a primary beam. The spectrometer includes a collimating tube extending along the common axis for baffling stray light and directing the primary beam through a sample.