Sequoia Scientific - Model LISST-Deep -Deep Submersible Particle Size Analyzer

• 4,000 meter depth rating (prior to 2020, rating was 3,000)
• Small angle forward scattering laser diffraction technology
• Measures particle size, concentration, beam attenuation, VSF, depth, temperature
• Self contained with internal programmable datalogger for autonomous data collection
• Externally powered
• Optional external battery pack, rated to 4,000 m depth
• USB connection to PC for programming, offloading and real-time size distribution displays
• Integrated depth and temperature sensor
• Power and integrate up to three external analog sensors
• 36 size classes
• Analog output of mean particle size and total volume concentration for CTD integration
• Real-time output of complete Particle Size Distribution

Using a red 670nm diode laser and a custom silicon detector, small-angle scattering from suspended particles is sensed at 32 specific log-spaced angle ranges. This primary measurement is post-processed to obtain sediment size distribution, volume concentration, optical transmission, and VSF. The LISST-Deep is programmed and operated like a LISST-100X. The LISST-Deep can be ordered as a type B (1.25-250µm) or type C (2.5-500µm) size range.

If you study the design of the LISST-Deep and compare it with the LISST-100X  it is clear that the mechanical design is very different from that of the LISST-100X. The optical path is more or less in the middle of the instrument, not at the end. This means that no accessories available for the LISST-100X will work with the LISST-Deep, with the exception of communication cables and instrument stands. No BioBlock, mixing chambers or path reduction modules are available for the LISST-Deep.

Also, because of the much thicker wall of the pressure housing, there is no room for internal battery packs as for the LISST-100X. The LISST-Deep must be powered externally at all times. This is typically achieved by connecting it to a CTD, getting power from the CTD. A cable for connecting to a CTD will be included, if the customer supplies Sequoia with the pin-out of the CTD upon ordering. Upon request, Sequoia can furnish a quote for a LISST-Deep external battery pack with cable for connecting to the LISST-Deep.