Abstract: A beam of radiation is directed into a liquid sample cell containing a sample to be analyzed in solution. The illumination emanating from the sample cell as a result of the beam of radiation from the radiation source is diffracted into a polychromatic spacially divergent beam and directed to a linear array of photovoltaic photodetectors with different spectral segments of the beam being intercepted by different photodetectors of the array. The signals from the photodetectors are separately and substantially simultaneously sampled and held to thereby obtain data usable for a high-accuracy wide-spectrum chromatogram.

Abstract: An achromatic beam splitter which is mechanically and thermally stable includes a first aperture, which aperture is overfilled, and an achromatic optical element. The aperture and element are preferably positioned in an optical plane having uniform illumination.

Abstract: Temperature sensitive photodetectors are temperature stabilized by coupling the photocathode of a photodetector in heat exchange relationship to a heated casting which acts as a heat source for the photocathode. The photocathode is coupled to the casting by a metallic Z-shaped bracket positioned on an insulating block with one base of the Z being coupled to the photocathode and the other base being coupled to a metal box through a Mylar insulating spacer, the box being directly mounted on the casting. A printed circuit board associated with the photodetector is also mounted on the insulating block. The direct heat path from the heated casting through the Z-shaped bracket to the photocathode reduces the warm up time of the photodetector thereby more rapidly temperature stabilizing the photodetector.

Abstract: A spectrophotometer detector cell assembly having improved sensitivity, has a cell defined by a bore through a body and closed at the ends by radiation transparent windows with inlet and outlet passages through the body to the bore, so that radiation passed through the sample fluid flowing through the bore is detected by a photodetector. The body, which is made of a thermally conductive material, is a large thermal mass is relation to the volume of the cell and a tubular inlet conduit, also made of a thermally conductive material, wraps around the body and connects to the inlet passage so that fluid flowing into the bore will tend to reach a stable temperature due to the heat sink effect of the body and conduit thereby stabilizing the refractive index of the fluid in the bore and enhancing the sensitivity of the photodetection.