D.  SMM/THz Gas Sensors:  A SMM/THz gas sensor needs a core spectrometer, such as described in Section V.C, packaged with a gas sampling system and appropriate operations software.  We have recently described such a system [1].  The sensor is self-contained, including gas handling and computation, in a standard 19 in equipment rack format, with a height of 5.25 in and a depth of 18 in. Its core spectrometer provides absolute specificity (probability of false alarm <<10-10) on a mixture of 32 gases. It is capable of automated analysis with a cycle time of <10 minutes and returns quantitative results for each gas in the mixture.  The system can analyze either a prepared mixture or a dilute sample of air via automated and software selectable sorbent preconcentration strategies.  In the sorbent mode a sensitivity of ~ 2 ppt is demonstrated for acetonitrile.


V.D.1 Strategies and Design Space

V.D.2 The Vacuum Preconcentration System

V.D.3 Sorbent Tubes and Sorbent Material Selection

V.D.4 Sensitivity


[1] C.F. Neese, I.M. Medvedev, G.M. Plummer, A. Frank, C. Ball, F.C. De Lucia, IEEE Sensors Journal, 12 (2012) 2565-2574.


Back to home page