The analyser is based on a specially designed Pyrex quartz ionisation cell in which the sample gas flow is ionised in a high voltage alternating electrical field with consequential emission of light. The instrument has ranges of both 0-10 & 0-100 vpm with a sensitivity of less than 1 vpm. A narrow spectral band corresponding to one of the specific light emission wavelengths of nitrogen is filtered by a narrow band-pass composite interference filter and then detected by a photomultiplier tube.
....
