Detector for distant gas clouds - uses raman effect and concave holographic spectrometer grating

摘要

The detector is mounted on a platform which moves in azimuth and elevation about horizontal and vertical axis. These movements are controlled by motors and position detectors. The beam from a laser transmitter is reflected by a mirror towards a gas cloud. Reflected rays received by a telescope are filtered for application to the concave holographic grating of a spectrometer. Rays corresponding to the frequencies of particular gases are received by fibre optic elements and directed onto a modulating disc. A photomultiplier converts these signals into electrical signals for processing of intensity and thus gas quantity.