LTS100 laser temperature sensor

Technical Description

A compact open-path spectrometer has been developed for measuring concentrations of selected species and gas temperature. The system is composed of a fiber-optically-delivered diode laser source, a photodiode detector, control electronics, and a PC-based signal processing unit. Species that have been demonstrated to date include H2O, CO2, NH3, and O2. Other species may be possible using lasers at different wavelengths.

Capability/Advantages over other technologies

Many current sensors for oxygen and other species rely on electrochemical cells that require physical contact between the sensor and the gas sample being interrogated. Such sensors can degrade over time due to “poisoning” of the sensing material by the gas sample, and are typically limited to close-range measurements. The laser spectrometer provides an all-optical measurement that is truly non-intrusive. The sensor does not degrade over time, and enables measurements at a distance, or inside vessels through transparent walls or windows.


Potential applications include leak detection, industrial processes, and homeland security. Measuring concentrations of H2O, CO2, NH3, and O2 non-intrusively from a distance would be valuable in a number of industries involving combustion, or for quality control on production lines. H2O concentration and temperature measurements may be used for optimizing combustion in a glass furnace. In coal fired power plants, NH3 concentrations would help to optimize the performance of selective catalytic reduction of NOx. Gas temperature measurements can be used to prevent slagging by ensuring that the ash fusion temperature is not exceeded. In the pharmaceutical industry, oxygen concentration measurements can be used for detecting leaks in vials on a production line. Homeland security applications that might benefit include monitoring of ambient air for explosives or poisonous gases.