Infrared optoacoustic gas analyzer having an improved gas inlet system

In a gas analyzer system:

• infrared optoacoustic gas analyzer means having an optoacoustic detector cell for containing a volume of gas to be analyzed at a pressure in excess of 10 torr and into which volume of gas modulated infrared radient energy is directed to produce modulated absorption of infrared energy by said gas under analysis resulting in producing a modulated pressure in said detector cell which is detected by a pressure sensitive detector;
• gas inlet system means for introducing gaseous material from a source into said optoacoustic detector region of said infrared optoacoustic gas analyzer means;
• said inlet system means including membrane separator means having a membrane of the type which has a higher value of diffusion conductance to a first gaseous component than to a second gaseous component of a gas mixture to be analyzed, said membrane separator means being dimensioned and arranged for diffusion therethrough of amounts of said first gaseous component at a sufficient rate for detection in the optoacoustic cell;
• means for diffusing a portion of said gas mixture through said membrane of said membrane separator means so as to conduct said first gaseous component through said membrane with a higher value of conductance than that of said second gaseous component;
• and
• means for conducting said separated first gaseous component of said gas mixture at a total pressure in excess of 10 torr into the optoacoustic detection region of the optoacoustic gas analyzer.

In a method for analyzing a gas mixture having first and second gaseous components therein, the steps of:

• directing modulated infrared radiant energy through an optoacoustic detector cell containing the gas mixture to be analyzed for producing a modulated absorption of infrared energy by the gas resulting in producing a modulated pressure wave which is detected by a pressure sensitive detector in gas communication with the cell;
• passing the gas to be analyzed from a source into the detector cell via the intermediary of a membrane separator of the type which has a higher value of diffusion conductance to a first gaseous component of the mixture than to a second gaseous component of the mixture so as to conduct said first gaseous component through said membrane separator with a higher value of conductance than that of said second gaseous component;
• and
• passing said separated first gaseous component of said gas mixture at a total pressure in excess of 10 torr into the optoacoustic detector region of the optoacoustic gas analyzer.

In a method for detecting the presence of a body, the steps of:

• incorporating deuterium in the body to be detected;
• detecting deuterium escaping from the body by passing the escaping deuterium through a membrane separator;
• reacting the deuterium having passed through the separator to produce an infrared absorption reaction product compound;
• passing the reaction product compound into the optoacoustic detector cell of infrared optoacoustic detector for detection thereof.

In a method of petroleum exploration, the steps of:

• traversing an area to be explored with an infrared laser optoacoustic gas detector and detecting at least one gaseous component in the atmosphere as a function of position in the area to be explored and such gaseous component being associated with buried deposits of petroleum, such detected gaseous component having diffused from the region of the buried deposit through the overburden and escaped into the atmosphere, and wherein the step of detecting the gaseous component in the atmosphere includes:
• feeding a sample of the gaseous atmosphere to be analyzed through a membrane separator having a membrane of the type which has a higher value of diffusion conductance to a first gaseous component of the mixture than to a second gaseous component of the gas mixture to be analyzed so as to conduct said first gaseous component through said membrane with a higher value of conductance than that of said second gaseous component;
• and
• conducting said separated first gaseous component of said gas mixture at a total pressure in excess of 10 torr into the optoacoustic detector region of the gas detector.