UV-VIS light spectroscopy system for outdoor trace gas measurements by Multiple Axes Differential Optical Absorption Spectroscopy (MAX-DOAS) method High quality instruments for scientific applications

EnviMeS offer a variety of custom made MAX-DOAS instruments for measurements of trace gases with the DOAS technique in the atmosphere. They range from instruments designed for permanent installation and long term measurements to mobile field instruments. Depending on the application different measurement sensitivities are required. We offer the application of standard detectors and high grade detectors using a back thinned sensor.

In all systems the scattered sunlight is collected by an optical system with a telescope and guided with fibers to a spectrometer. The telescope can be moved to different elevation angles Data acquisition and instrument control are performed with the internal PC or an external PC. The systems are optimized in terms of high measurement accuracy with small measurement setups. Therefore it uses compact spectrometers with good cost-benefit which allow smaller and mobile systems. To achieve high measurement accuracies the systems are optimized for high light throughput, good spectral resolution, use of high quantum efficiency detectors, accurate temperature control of spectrometers, low spectrometer stray light, small telescope opening angle, accurate telescope (scanner) positioning, automatic elevation angle correction and low electronic noise. The system is additionally optimized for low power consumption with the uses of a high efficient temperature controller and optional a low power embedded PC.

System Configuration:

Separate Spectrometer Scanner System

The system consist of two components: indoor module with temperature stabilized spectrometer(s) and electronics and outdoor optical system (scanner) for light collecting. Both components are connected with an optical fibre (typical 10m), power and controlling cables. This system is recommended for long term or permanent installations, or measurements at very cold or warm environments, as the sensitive spectrometers and electronics can be set-up indoor in a dry and relative temperature stabilized environment. Thus longer lifetimes and better measurement accuracies can be achieved.

Compact MAX-DOAS System

The compact MAX-DOAS combines the optical system with the spectrometer and electronic unit in one housing. It is designed for the direct application in the filed and can be mounted on a frame or on a tripod. Due to the compact construction it can be fast applied to any field location or locations without any infrastructure. This system is optimal for short field observations or mobile applications.