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Microcross-section detector

There are many convenient devices for measuring the composition of two-component gas mixtures currently in use in gas chromatography. Foremost among these devices are thermal conductivity cells, flame ionization detectors, gas density balances, and the microcross-section detector. These sensors provide a continuous signal suitable for feeding into a chart recorder. When coupled with an accurate flow meter, such devices enable a reaction to be followed from the gas composition downstream from the pellet. [Pg.215]

The microcross-section detector is a somewhat similar device, differing mainly in that ionization of the gas stream is produced by tritium adsorbed on a suitable substrate and only 75-100 V are maintained across the electrodes. To avoid stripping the trituim from the substrate, the gas temperature must be below 200°C and an AEC license is required to use such a detector. The device is most useful in analyzing mixtures of hydrogen and another gas, although it might be suitable for other gas mixtures. The current flow in these sensors is dependent on the molecular cross section (which is simply the sum of the well-known cross sections of the constituent atoms) and calibration is not required for all gas mixtures. [Pg.216]


See also in sourсe #XX -- [ Pg.216 ]




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