Grantee Research Project Results
Final Report: Environmental Monitoring Compact Raman LIDAR System Utilizing APD Array Detectors
EPA Contract Number: 68D99066Title: Environmental Monitoring Compact Raman LIDAR System Utilizing APD Array Detectors
Investigators: Karger, Arieh
Small Business: Radiation Monitoring Devices Inc.
EPA Contact: Richards, April
Phase: I
Project Period: September 1, 1999 through March 1, 2000
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (1999) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , SBIR - Monitoring , Small Business Innovation Research (SBIR)
Description:
Light Detection and Ranging (LIDAR) is an attractive technique for remote monitoring applications. In LIDAR systems, a short laser pulse is directed towards a remote location, and a small fraction of the laser energy is scattered from the remote location and detected by a sensitive detector. By analyzing the round-trip time-of-flight of the laser signal, the range can be determined. While a number of different LIDAR techniques have been developed, Raman LIDAR appears to be one of the most promising since each molecular species exhibits a unique Raman scattering signature. Thus, Radiation Monitoring Devices, Inc. (RMD) has chosen to develop a Compact UV Raman LIDAR system for environmental pollution monitoring. During Phase I of this SBIR project, RMD experimentally demonstrated the capabilities of Raman LIDAR under laboratory conditions and developed the design of a prototype Compact UV Raman LIDAR that will be completed in Phase II. In addition, we have incorporated marketing and commercialization considerations in order to insure that the Compact UV Raman LIDAR system will be a successful product.The design goal of this SBIR project is to produce a Compact UV Raman LIDAR system at low cost. Cost savings are achieved because the proposed design uses RMD's unique µ-APD detector arrays, which are capable of single photon detection with high efficiency at room temperature. In addition, these µ-APDs can be operated with a single 40V power supply and exhibit high enough gains that expensive amplification electronics can be eliminated. By using an array, it will not be necessary to incorporate wavelength scanning, significantly simplifying the system design and manufacture. The system will simultaneously detect all the wavelengths of interest, making it practical to utilize long acquisition times and signal averaging to improve the signal to noise. Finally, the Compact UV Raman LIDAR will utilize a quadrupled Nd:YAG laser, resulting in a very compact solid state design.
Phase I of this SBIR consists of three major tasks: 1) experimental proof-of-concept by obtaining Raman LIDAR returns in the laboratory; 2) System analysis to refine the estimation of the Compact UV Raman LIDAR sensitivity; and 3) Design of the prototype system to be built and tested in Phase II. RMD has successfully completed all of the Phase I tasks and is confident that prototype development during Phase II will lead to commercialization of a family of products based on this Compact UV Raman LIDAR technology.
Summary/Accomplishments (Outputs/Outcomes):
The laboratory experiments included the design and construction of a custom Raman LIDAR test chamber. Various test gases were introduced into the Raman LIDAR test chamber and the Raman backscatter returns were analyzed as a function of wavelength and gas pressure. The results indicate an excellent ability to identify and quantify the test species. By analyzing the sensitivity of these Phase I laboratory experiments, we estimate that the Compact UV Raman LIDAR system will be capable of achieving better than 40 parts per million (PPM) sensitivity.In addition to the laboratory experiments, we developed and analyzed the design of the Phase II prototype. This design included a preliminary optical design of the collection telescope and the wavelength analysis systems. The optical design was used to estimate the collection efficiency of the Compact UV Raman LIDAR. The resulting analysis indicates that the smokestack pollution monitoring system will be capable of detecting various pollutants with better than 100 PPM sensitivity at a ranges of 100-200 m.
Finally, RMD completed the commercialization analysis with Foresight Science and Technology, Inc. (FST). FST found that RMDs unique µ-APD detector arrays are excellent candidates for commercialization due to their very high sensitivity and the ability to rapidly gate the detector elements. RMD is actively engaged in commercializing this technology. We believe that the development of the Compact UV Raman LIDAR will assist in this commercialization effort and result in a viable family of products.
Conclusions:
RMD has successfully completed all of the Phase I tasks and demonstrated the capabilities of Raman LIDAR for environmental monitoring applications. The system design developed during Phase I will lead to the successful completion and field testing of the prototype Compact UV Raman LIDAR system in Phase II. The Compact UV Raman LIDAR system is expected to result in a variety of commercial environmental monitoring products, including smokestack monitoring, automobile pollution monitoring, and fence line monitoring.Supplemental Keywords:
Raman LIDAR, Automobile Emissions, Environmental monitoring, Geiger-mode APD, Pollution Monitoring, Avalanche Photodiode, Smokestack Emissions, APD array., Economic, Social, & Behavioral Science Research Program, Air, Toxics, Ecosystem Protection/Environmental Exposure & Risk, air toxics, HAPS, Monitoring/Modeling, Engineering, Chemistry, & Physics, Economics & Decision Making, Market mechanisms, monitoring, sulfur oxides, environmental monitoring, air pollutants, UV, ambient monitoring, methane emissions, air pollution, ambient emissions, methane, Sulfur dioxide, atmospheric dispersion, carbon dioxide, pollutants, real time monitoring, cost effective, Sulfur Oxides (SO2), cost effectivenessThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.