OPTICAL ABSORPTION METER.
Gary D. Gilbert, Richard C. Honey, Ronald E. Meyers, Glenn Sorenson · Defense Technical Information Center (DTIC) · 1969
The report describes the second-generation absorption meter (a-meter). The system uses two self-powered pulsed light sources and two detectors. One source is equidistant from the two detectors and provides an in-situ calibration method. The other source is located about one-third as far from one detector as from the other detector. The detectors and light sources operate at ambient pressure, in contact with the water. Fifty-ohm coaxial line is used to transmit the signals to the deck. A solid-state circuit on deck provides measured values of a (the absorption coefficient) directly on a digital voltmeter. A signal is also provided with which to drive a chart recorder. (Author)