From: Quarterdeck Volume 5, Number 1, Spring 1997

Laser In-Situ Scattering and Transmissometer (LISST)

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1. As the LISST descends through the water it projects a laser beam toward ring-shaped detectors on the main body of the instrument.

2. This top view of LISST's laser and detectors show how the instrument uses scattering to measure particle sizes.

3. From the inside surface of the crossbar a laser beam shines on particles in the water.


4. Particles scatter the laser light at different angles depending on particle size. Small particles scatter light toward outer rings of the detector while large particles scatter light toward inner rings.

5. The amount of scattered light detected by each ring is recorded by the instrument's internal computer. These data are later converted into graphs of the abundance of particles of each size.

6. A pressure case houses a battery to power the instrument and a microprocessor to collect the data.

7. Waterproof connectors link LISST to other instruments and to conducting cable. Digital signals deliver data from the instrument to the surface.

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Last Modified: 04 May, 2000