Sequoia LISST-200X

Measures Particle Size Distribution and Concentration; and Optical VSF

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The LISST-200X marks a major advance in technology of our workhorse LISST-100X submersible laser-diffraction instruments used for use in rivers, streams, ports, harbors, coasts and oceans. It also measures the small-angle optical volume scattering function (VSF).

Similar to LISST-100X, it too holds calibration for life.

  • Measures Particle Size and Concentration
  • Particle Size Range:  1.0 to 500 microns
  • Small angle VSF: 0.039 to 13.8 degrees.
  • Extended Depth Rating: 600 meters
  • Automated Pass/Fail report on Backgrounds
  • Half the physical size of the LISST-100X
  • Smarter data file structure
  • Analog output of size and concentration
  • Plug and Play Compatible with most CTDs


The LISST-200X is a submersible laser-diffraction based particle size analyzer designed to measure particle size and concentration in rivers, streams, ports, harbors, coasts and oceans, whether for biological, sediment transport, or environmental monitoring needs.

Applications include sediment transport studies, harmful algae blooms, oil spill dispersion effectiveness, dredge plume monitoring, etc.  For marine optics applications the LISST-200X provides the small-angle Volume Scattering Function.

20 years of LISST-100X experience combined with feedback from users has led us to create this Smaller, Deeper, and Smarter Particle Size Analyzer.

LISST-200X LISST-100X Comparison

The LISST-200X is significantly smaller than the LISST-100X but it has also been made stronger and is now able to make measurements at twice the depth: up to 600 meters. Improved optics cover the size range 1-500 microns in 36 size classes. The optics are also more robust and have improved rejection of ambient light. A superior depth sensor and a faster temperature sensor improve profiling data. The 25mm optical path allows a wider working range of particle concentrations. Auxiliary information, such as calibrations and background files, are stored in the saved data file. All information needed to process the data are included in this single file, therefore alleviating the need for tracking multiple files.

The LISST-200X also outputs the Mean Size and Total Concentration as analog voltages while simultaneously storing the full size distribution internally for later downloading. This allows real-time monitoring of summary data during profiles via existing CTD interfaces.

LISST-200X Connector Endcap

A full range of accessories are available for the LISST-200X including small and large External Battery Packs, Path Reduction Module, Full Path Flow Through Chamber, Large Volume Test Chamber, Mixing Chamber (coming soon), BioBlock Anti-Fouling Shutter (coming soon), Settling Column (coming soon) and towed and AUV configurations.

This next generation particle sizer is simply smaller, deeper and smarter, whether for lab or field use.




  • Small-angle forward scattering
  • 32-ring custom photodiode Ring Detector + 4 large angle detectors
  • 25 mm optical path


Parameters measured

  • Particle Size Distribution from 1.0-500µm in 36 size ranges
  • Depth (600 m max depth @ 0.01 m resolution)
  • Temperature @ 0.01 deg C resolution
  • Optical transmission @ 0.1% resolution
  • Volume Concentration @ 0.1µl/l resolution
  • Volume Scattering Function from 0.039 to 13.8 degrees in water
  • Analog output of Mean Size and Volume Concentration

Operating Concentration range

  • Optical transmission from 0.3-0.99 (30-99%)
  • Concentration from ~ 0.5-700 mg/l (grain-size dependent)


Mechanical and electrical

  • Dimensions 10.03 cm (3.95”) dia., 63.9 cm (25.2”) long
  • Weight: 5.4 kg (11.8 lbs) in air, 1.7 kg (3.8 lbs) in water
  • 600 meter depth rating
  • External power input: 12VDC nominal, 8-24VDC
  • Sampling rate: Up to 1 Hz
  • Current drain at 12V: 100mA Sampling, 8 mA between samples
  • Data storage: 1 GB (~12,500,000 size distributions)

LISST-200x dimensions




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