Unrestricted.2016-11-142011-02-182016-11-141984-05http://hdl.handle.net/2346/14743Surface geochemistry studies are valuable methods of petroleum prospecting. Atmospheric methane surveys can outline those areas where detailed geochemical studies need to be conducted. This report describes a field device capable of measuring small changes in methane concentration in the near surface atmosphere. Methane concentration is determined by measuring the attenuation of the 3.3922y He-Ne line in a pressurized gas flow cell due to absorption by methane. A second He-Ne laser line at 3.3912 p, which is only weakly absorbed by methane, is used as a reference signal to compensate for laser intensity fluctuations and scattering by water and dust. This system s fast, allowing measurements to be made from a moving vehicle- Also, the system allows for continuous sampling of the changing methane concentration as opposed to point measurements.application/pdfengLaser spectroscopyPetroleum -- GeologyGeochemical prospectingNatural gas -- GeologyMethaneThesis