Precision Measurement Engineering, Inc.
The Laser Turbidity sensor is designed to be used with SCAMP's fluorometer. The sensor is shown in the picture below. It is the black cylinder located at the center of the end cap, amoung the other sensor sealing nuts.
The Laser Turbidity sensor operates in a similar way to the other SCAMP Turbidity sensor. The sensor housing is shown in the following drawing. The sensor emits pulsed infrared light from a laser diode located in the cavity shown. These light pulses illuminate the water directly outside above the cavity. The photo diode detector within the cavity shown views a small section of the illuminated volume. If particles (turbidity) are present in the viewed volume then some of the light will be scattered into the photo diode and detected. The small electrical signal that results is amplified and recorded within SCAMP.
The turbidity sensor components and electronic circuit are supplied to PME by D&A Instruments. The housing shown above is manufactured by PME and parts supplied by D&A are assembled into it.
The Laser Turbidity sensor differs from SCAMP's other turbidity sensor in two ways. First, it can be used concurrently with SCAMP's fluorometer. Second, it is more sensitive to turbidity since the laser emits somewhat more light and the viewing angle used in the Laser Turbidity sensor is better to receive scattered light.
The sensor has two sensitivities, selectable via a jumper on the circuit board within SCAMP. Highest range of sensitivity is 0 to 300 NTU.