AtmosTM gas cells are a range of non-heated long pathlength cells which can be used for applications which require a longer path of transmission at room temperature.
The AtmosTM series comprises gas cells of three different sizes:
- 1.33 L volume – the T5 (GS24205 series)
- 2.6 L volume – the T10 (24210 series)
- 4.7 L volume – the T20 (24220 series)
Each of the series is sealed using Viton perfluoroelastomer 0-rings.
As the volume of the cell increases, so does the maximum possible pathlength with some overlap between each of the different models. For example, a pathlength of approximately 2 m (2.1 m for T10) is possible using any of the cells.
For a given gas concentration, the smaller volume cell (the T5) will provide the best pathlength: concentration ratio, provided a pathlength of 2.0 m is all that is required. The longest pathlength possible is achieved using the T20, which can achieve a pathlength of 20.0 m
Specac provides a guide which can be used to determine the optimum pathlength for each concentration of gas - Choice of Gas Cells for Pathlength/Concentration.
Working of the AtmosTM Gas Cells
AtmosTM cells can be produced from either a borosilicate gas (allowing experiments to take place at 28 psi, 1 atm above ambient pressure) or, if required, from aluminum coated with nickel (allowing experiments to take place at 125 psi). Both cells can be ran at vacuum conditions and a pressure gauge system can be provided to monitor gas pressure within cells.
The windows of AtmosTM cells can be provided in either CaF2, ZnSe, or KBr, for experiments at higher pressures using a metal bodied cells the window should be produced using KBr to withstand the higher pressures. In addition to pressure requirements, windows should be chosen that transmit the frequencies required to analyze gases of interest, which are also resistant to reacting with the specific vapors.
The mirrors for AtmosTM cells are provided with a gold coating, which protects against chemical reactions, and are mounted on a support of either stainless steel or anodized aluminum.
This information has been sourced, reviewed and adapted from materials provided by Specac.
For more information on this source, please visit Specac