Scatter and transmission meter LISST-100/200X | Flanders Marine Institute
 

Flanders Marine Institute

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Scatter and transmission meter LISST-100/200X

The scatter and transmission meters LISST-200X and its predecessor LISST-100X (LISST: Laser In-Situ Scattering and Transmissometry) are based on laser diffraction, a widely used technique to investigate detailed particle sizes and volume concentrations. That is why the LISST-units can also be used to detect oil droplets and their size and concentration in the water or to investigate the distribution of plankton. The LISST-100X and 200X are commonly deployed on a tripod and can be placed at a depth of up to respectively 300 and 600 m.

How does a LISST-100/200X work?

The scatter and transmission meter LISST-100/200X (Laser In-Situ Scattering and Transmissometry) is based on laser diffraction. Laser diffraction uses the principle that a spherical particle of a known size, composition and color scatters light in a manner that allows the shape to be defined and calculated. Moreover, the scattering patterns are unique for particles with a different size and composition.

Inside the LISST-100/200X, a laserdiode and collimator are located. The 32 detector rings cover 32 ranges of angles over which the light scattering is measured. This measurement is mathematically inverted to get the size distribution, and scaled to obtain the volume scattering function (VSF). The size distribution is presented as the concentration with units of micro-liters per liters (µl/l) in each of the 36 log-spaced size bins (32 bins for the LISST-100X). The time and date, water depth, optical transmission and temperature are also recorded.


Scattering signature of tree spherical particles with diameters of 20,5, 20 and 7 µm. ©sequoiasci.com

  Photos

Usefulness of a LISST-100/200X?

The main use of the LISST-100X and 200X is to research the size distribution and volume concentration of particles.

Some studies:

 

  • Research of the concentration and particle distribution of sediment in the water column:

 

This is executed in the framework of assessing the physical impact of beam trawling
Depestele, J. (2015)

Technical details

The LISST-200X of VLIZ measures particles with a size order between 1 and 500 µm. Its predecessor, the LISST-100X, has a measuring range of 2,5-300 µm.

Technical information:

  • Diode laser 670 nm, 1 mW
  • 32-ring custom photodiode detector (+ 4 large angle detectors for the LISST-200X)
  • LISST-200X: 10,03 cm diameter, 63,9 cm height
    LISST-100X: 13,3 cm diameter, 87 cm height
  • LISST-200X: weight of 5,4 kg (in air); 1,7 kg (in water)
    LISST-100X: weight of 11 kg (in air); 3,6 kg (in water)
  • More technical details: click here

How to borrow a LISST-100X or 200X?

For more information about our rental service, please contact VLIZ

Use and conditions

Note: if you use the LISST-100X or 200X of VLIZ as a scientist, please refer to it in your publications as: 'This work was supported by data & infrastructure provided by the Flanders Marine Institute (VLIZ)'.