Sequoia LISST-ABS Acoustic Sediment Sensor

The Sequoia LISST-ABS Acoustic Sediment Sensor is a low-cost sensor designed specifically for measuring suspended sediment concentration at a single point.

Features

• Uses acoustic backscatter to measure the concentration of particles suspended in water
• Wide dynamic range of concentrations from 1mg/L to 30 g/L
• Plug-and-play interface with X2, X2-SDL, and X2-CB data loggers and telemetry systems

Details

Overview
The Sequoia Scientific LISST-ABS is a single-point acoustic sediment sensor, designed to provide higher quality data than optical turbidity sensors. The LISST-ABS internally measures the Attenuation Corrected Backscatter (ACB). The ACB value is converted to an Uncalibrated Concentration (Cu) and then output. To convert the Uncalibrated Concentration to sediment concentration, a simple multiplier is required. The multiplier, or Cal Factor, is dependent on the specific type and size of sediment being measured. When a user recalibrates an instrument, this multiplier is updated.

Mechanics
The Sequoia Scientific LISST-ABS employs a high frequency of 8 MHz. Calibration of backscatter signal strength with sediment concentration remains nearly constant over a wide particle size range, ~40-500 microns. Over this size range, the Sequoia Scientific LISST-ABS calibration changes only about ~±30%. In contrast, over this same size range, optical turbidity sensors would change calibration by ~ ±600% over its mean value.

Remote Monitoring
The LISST-ABS sensor offers a plug-and-play interface to the full line of NexSens X2 data loggers and telemetry systems. The X2 is available for pole-mount deployments with solar charging near streams and rivers; the X2-SDL includes an integrated 16 D-cell alkaline battery pack for subsurface deployments; and the X2-CB is designed for integration on CB-Series data buoy platforms.