Abstract: Delivery of gas by a pulsed gas delivery device is monitored using a sensor. The sensor may include a source that generates radiation at a spectral range that includes an absorption frequency of the gas being delivered. The radiation is transmitted through a receptacle into which the delivered gas has been received. A detector detects the intensity of the radiation that reaches the detector from the source after transmission through the gas in the receptacle. A controller measures a precise quantity of the gas that was delivered by the gas delivery device, by determining from the detected intensity the amount of the radiation that was absorbed by the gas in the receptacle. The controller monitors in real time the delivery of the gas, by adaptively adjusting the quantity of gas being delivered to a desired quantity. The sensor and controller can also monitor for failures or for out-of-specification behavior of the gas delivery device.

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.

Abstract: A modular system for gas analysis has a first gas cell that receives and passes at least a portion of an infrared light beam through at least a portion of the first gas cell. A second gas cell disposed proximal to the first gas cell receives and passes at least a portion of the infrared light beam from the first gas cell through at least a portion of the second gas cell. At least a portion of the first gas cell and at least a portion of the second gas cell define a light path having an effective length. The system includes a means for adjusting the effective length of the light path to vary a property of the infrared light beam. Methods of making a variable effective length light path and methods of making a gas detector are also disclosed.

Abstract: Delivery of gas by a pulsed gas delivery device is monitored using a sensor. The sensor may include a source that generates radiation at a spectral range that includes an absorption frequency of the gas being delivered. The radiation is transmitted through a receptacle into which the delivered gas has been received. A detector detects the intensity of the radiation that reaches the detector from the source after transmission through the gas in the receptacle. A controller measures a precise quantity of the gas that was delivered by the gas delivery device, by determining from the detected intensity the amount of the radiation that was absorbed by the gas in the receptacle. The controller monitors in real time the delivery of the gas, by adaptively adjusting the quantity of gas being delivered to a desired quantity. The sensor and controller can also monitor for failures or for out-of-specification behavior of the gas delivery device.