D & A will design and build a custom turbidity sensor for your application. The core of our OEM sensors is a proprietary, micro-size, laser-based, electro-optical system shown next to a U.S. dime. As more than 53 sensor months of testing has proven, the time and temperature drift of this system is very low. The combined drift of electronics, source, and detector is less than 2% per year of continuous operation and less than 0.05 % per °C of temperature change. We achieve this low drift with a 2000-hour burn-in process, spectrally matched photodetectors, and automatic power control (APC) with a very stable laser-driver circuit. These characteristics can be implemented in a variety of packages. Our OEM sensors are used in ground-water monitoring systems, wiped turbidity probes, and process-control instrumentation. The latter sensor package is plumbed with a high-pressure water jet for cleaning the sapphire sample windows and providing continuous, virtually maintenance-free operation. OEM designs are available in a 650, 780, and 850 operating wavelengths. Nonlinearity in the low turbidity range (< 250 NTU) is guaranteed to be less than 1%, and with 3rd-order linearization, 3% to 1500 NTUs.

Mail-box package

Process control sensor