Portable remote laser sensor for methane leak detection
A portable laser system for remote detection of methane gas leaks and concentrations is disclosed. The system transmitter includes first and second lasers, tuned respectively to a wavelength coincident with a strong absorption line of methane and a reference wavelength which is weakly absorbed by methane gas. The lasers are aimed at a topographical target along a system axis and the beams successively interrupted by a chopper wheel. The system receiver includes a spherical mirror for collecting the reflected laser radiation and focusing the collected radiation through a narrowband optical filter onto an optial detector. The filter is tuned to the wavelength of the two lasers, and rejects background noise to substantially improve the signal-to-noise ratio of the detector. The output of the optical detector is processed by a lock-in detector synchronized to the chopper, and which measures the difference between the first wavelength signal and the reference wavelength signal.
- Assignee:
- The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
- Patent Number(s):
- US 4489239
- OSTI ID:
- 5796767
- Resource Relation:
- Patent File Date: Filed date 24 Sep 1982; Other Information: PAT-APPL-423016
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
LEAKS
DETECTION
REMOTE SENSING
METHANE
MONITORS
DESIGN
NATURAL GAS DISTRIBUTION SYSTEMS
MONITORING
PIPELINES
BACKGROUND NOISE
LASER MIRRORS
LASER RADIATION
LASERS
OPTICAL FILTERS
PORTABLE EQUIPMENT
SIGNAL-TO-NOISE RATIO
WAVELENGTHS
ALKANES
ELECTROMAGNETIC RADIATION
ENERGY SYSTEMS
EQUIPMENT
FILTERS
HYDROCARBONS
MEASURING INSTRUMENTS
MIRRORS
NOISE
ORGANIC COMPOUNDS
RADIATIONS
032000* - Natural Gas- Transport
Handling
& Storage
420300 - Engineering- Lasers- (-1989)