||Development of Range Squared and Off-Gating Modifications for a Lidar System.
Bethk, George W. ;
||General Electric Co., Philadelphia, Pa. Space Div.
Optical radar ;
Plume detection ;
Range gating ;
Air pollution ;
Remote sensing ;
Photomultiplier tubes ;
Data processing ;
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
The study was intended to eliminate the dorminant source of error in the remote measurement of smoke-stack plumes using lidar, and to improve the data presentation of the lidar transmittance measurement. The use of a special grid-controlled photomultiplier tube and off-gating system has resulted in a large reduction of photomultiplier tube afterpulsing which has been the principal problem limiting the accuracy of plume transmittance measurements. A range-correcting time-squared amplifier has also been developed which permits much faster and more convenient data reduction than formerly possible. The above two developments have been adapted to an existing van-mounted EPA lidar system; and the improved overall system accuracy has been evaluated using both opaque and semi-transparent targets of known transmittance. (Author)