Monitoring of volatile organic components associated with waste disposal activities and gas pipeline leaks with a man-portable mid-infrared DIAL

摘要

LaSen, Inc. is continuing development of compact and rugged lidar systems for ground-based and airborne detection of volatile organic components (VOC) in the mid-infrared spectral region. The first-generation ground-based sensor (Lidar I) measures 0.19 m~3 and weighs 55 kg. Throughout 2001, Lidar I is undergoing a series of field tests in south-central New Mexico, USA. The tests completed to data include measuring methane level at rural dumpsites and monitoring emissions from contaminated soil at a diesel fuel spill site. To support the lidar programs, LaSen developed a compact tunable midinfrared laser source based on an intracavity optical parametric oscillator. The laser source delivers up to 1.3 mJ of midinfrared energy per pulse and is angular tuned in the 3-5-μm band through a servo-controlled loop. A piezo-driven tuner for fast switching between "on" and "off" lines is available as an option. Lidar I performance characteristics relevant to detection of various VOC are discussed. The second-generation sensor (Lidar II) is undergoing development and is scheduled for tests in the fourth quarter of 2001. Lidar II is a re-packaged version of Lidar I, with a significant decrease in both weight and size. Although not specifically designed for an airborne platform, Lidar II will be capable of demonstration flights on board a helicopter operating in a look-down topographic mode.