Multigas Monitoring and Detection System

Abstract

A spectroscopic detection system is described for monitoring ambient air for toxic chemical substances. The system can be a compact, portable multiple gas analyzer capable of detecting and discriminating a broad range of chemical constituents including various nerve and blister agents as well as toxic industrial chemicals at low or sub part per billion (ppb) levels. The system minimizes false alarms (e.g., false positives or negatives), features high specificity, and can operate with response times on the order of a few seconds to a few minutes, depending on the application. The system can be an entirely self-contained analyzer, with a Fourier Transform Infrared (FTIR) spectrometer, a gas sample cell, a detector, an embedded processor, a display, power supplies, an air pump, heating elements, and other components onboard the unit with an air intake to collect a sample and an electronic communications port to interface with external devices.

1 - 28 . (canceled) 
   
   
       29 . A method of optically measuring a trace gas in a gas sample, comprising:
 providing a portable absorption spectrometer comprising a sample cell including a field surface at a first end and an objective surface at a second end in a confronting relationship to form a folded path;   flowing the sample gas through the sample cell;   optimizing the volume of the sample cell and the number of passes of a beam of radiation in the folded path to maximize throughput of the beam of radiation propagating in the sample cell to detect the trace gas having a concentration of less than about 500 ppb in the sample gas; and   diluting the trace gas to an acceptable level based on the detected trace gas.