Upgrades are now available to operate the TGA100A with a thermoelectrically cooled (TEC) laser, enabling the analyzer to no longer require liquid nitrogen refills. This upgrade requires a new TEC laser module, TGA200A Input Module, TGA200A Output Module, and TGA TEC software. Additional upgrades may be available for software-controlled temperature control, detectors, power supplies, etc. Contact Campbell Scientific for more information. The TGA100A Trace-Gas Analyzer measures trace-gas concentration in an air sample using tunable diode laser absorption spectroscopy (TDLAS). This technique provides high sensitivity, speed, and selectivity. The TGA100A is a rugged, portable instrument designed for use in the field. It can measure one of a large number of gases by choosing appropriate lasers and detectors. It incorporates several features that make it ideal for measuring fluxes of trace gases using gradient or eddy-covariance techniques.