| 摘要 |
A novel enhanced infrared spectral light source employing gas discharge, to be designated hereafter as EISLS, and a detection system using such an EISLS lamp for gas detection of a given molecular gas, the lamp adapted to produce spectral radiation at selected, sharply defined, spontaneous emission frequencies in the infrared corresponding to an absorbing molecular rotation-vibration transition band of the given gas. According to one feature, a gas mixture within the chamber provides an excitable buffer gas and a quantity of the given gas, the buffer gas having a state excitable by the excitation means and matched to the given gas in the manner that energy from the buffer gas state can transfer via collisions to the given gas and excite the upper levels of the absorbing transition band, whereby resultant radiative decay of the upper levels to the lower levels of the absorbing transition band produces the desired selected spontaneous emissions from the given gas, enhanced by the buffer gas. The given gas may be placed in the chamber or may be produced by interactions of other gases and the electrical discharge within the chamber. According to another feature, in such an EISLS spectroscopic lamp which produces spontaneous emissions corresponding to an absorbing band and other undesired spontaneous emissions as a result of excitation of other levels, the parameters being selected to make the desired emissions have a decay time long relative to the decay time of the undesired emissions, means are provided to interrupt the excitation means periodically and to delay the utilization of emission from the lamp a time following the instant of each interruption to the period when the other levels and associated emissions are decayed and the given gas continues to emit at the desired transition. According to another feature an EISLS spectroscopic lamp which produces sharply defined spontaneous emissions corresponding to an absorbing band of a given gas is arranged to direct its emission along a detection path in which the given gas may appear, and is combined with means to provide a modulated magnetic field either in the detection path to cause modulation of the absorbing transitions of paramagnetic gas to be detected or in paramagnetic emitting gas in the lamp to cause frequency modulation of the emitted spectral radiation, and an electronic detection means is provided, responsive to the resultant modulated intensity reaching the detector, to enhance the detection sensitivity.
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