Our partner

Long-Pathlength Gas Cell - Atmos

From Specac

Atmos™ is a range of long pathlength gas cells for measuring the infrared spectra of trace gases and vapors. Available in fixed pathlengths for maximum versatility. Each cell has been individually optimized for maximum optical throughout and signal-to-noise.

Features

Robust internal optics making use of highly reflective and chemically inert gold coatings and mechanical mounts to reduce off-gassing into the cell from adhesives.
Optimized optical path to maximize throughput and signal-to-noise.
Reduced cell volume to minimize the time required for exchanging gases sample-to-sample.
Heating jacket option: Heatable to 200 °C using digital temperature controller.

Further information

Which pathlength should I choose?

The absorbance of a gas depends on the distance travelled by the IR light beam through the gas sample. The relationship between absorbance, A, concentration, C, and pathlength, L, is given by Beer’s Law: A = -log10 (I/I0) = a.C.L Atmospheric concentrations of gases are usually expressed in C.L units of ppm.m – the number of molecules that would be encountered by the infrared beam across a 1.0 m path. A gas at 0.1 ppm atmospheric concentration will absorb as much IR light over a pathlength of 100 m as would the same gas at 1 ppm over 10 meters or at 10 ppm over 1 meter. Accordingly, the pathlength of cell should be chosen to give absorbance values within the spectrometer’s linear range for a given concentration.