NEO Monitors LaserGas™ is using Tuneable Laser Absorption Spectroscopy (TLAS) i.e. a non-contact optical measurement method employing solid-state laser sources. Therefore, the sensor remains unaffected by contaminants and corrosives and does not require regular maintenance. The laser beam is coupled into a Herriott cell, where it is reflected multiple times between two spherical mirrors in order to enhance the analyser sensitivity. The MP monitor is a turn-key instrument. No other operations than connecting power, sample gas tubes and optional purge are required during installation. To avoid fouling of optical parts in the Multipass cell the cleanliness of the sample gas must be ensured. Filtering the sample gas in an appropriate extractive system may be required for some applications.