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Improving Ground Penetrating Radar Imaging in High Loss Environments by Coordinated System Development, Data Processing, Numerical Modeling, & Visualization

Description: Improving Ground Penetrating Radar Imaging in High Loss Environments by Coordinated System Development, Data Processing, Numerical Modeling, and Visualization Methods with Applications to Site Characterization EMSP Project 86992 Progress Report as of 9/2004.
Date: December 1, 2004
Creator: Wright, David L.
Partner: UNT Libraries Government Documents Department

Improving Ground Penetrating Radar Imaging in High Loss Environments by Coordinated System Development, Data Processing, Numerical Modeling, and Visualization Methods with Applications to Site Characterization

Description: The Department of Energy has identified the location and characterization of subsurface contaminants and the characterization of the subsurface as a priority need. Many DOE facilities are in need of subsurface imaging in the vadose and saturated zones. This includes (1) the detection and characterization of metal and concrete structures, (2) the characterization of waste pits (for both contents and integrity) and (3) mapping the complex geological/hydrological framework of the vadose and saturated zones. The DOE has identified ground penetrating radar (GPR) as a method that can non-invasively map transportation pathways and vadose zone heterogeneity. An advanced GPR system and advanced subsurface modeling, processing, imaging, and inversion techniques can be directly applied to several DOE science needs in more than one focus area and at many sites. Needs for enhanced subsurface imaging have been identified at Hanford, INEEL, SRS, ORNL, LLNL, SNL, LANL, and many other sites. In fact, needs for better subsurface imaging probably exist at all DOE sites. However, GPR performance is often inadequate due to increased attenuation and dispersion when soil conductivities are high.
Date: June 1, 2003
Creator: Wright, David L.
Partner: UNT Libraries Government Documents Department

Enhancements to and Characterization of the Very Early Time Electromagnetic (VETEM) Prototype Instrument and Applications to Shallow Subsurface Imaging at Sites in the DOE Complex

Description: The objective of this research is to enhance the state-of-the-art in electromagnetic imaging of the shallow subsurface in electrically conductive media where groundpenetrating radar (GPR) provides insufficient penetration and time domain electromagnetic (TDEM) systems provide insufficient resolution. This objective is being pursued by instrumentation enhancements to the existing very early time electromagnetic (VETEM) system coupled with physical and numerical modeling. Success in this endeavor will improve the speed and accuracy of waste pit and trench location and characterization, and could have additional applications to shallow DNAPL and LNAPL spill and cleanup monitoring, clay barrier integrity assessment, and landfill stabilization monitoring. This could result in significant savings in time and money during characterization, remediation, and decommissioning of facilities.
Date: June 1, 2000
Creator: Wright, David L. & Chew, Weng Cho
Partner: UNT Libraries Government Documents Department

Enhancements to and Characterization of the Very Early Time Electromagnetic (VETEM) Prototype Instrument and Applications to Shallow Subsurface Imaging at Sites in the DOE Complex

Description: Tests in July, 1998, of an improved version of the prototype VETEM system demonstrated improved depth of investigation at the Cold Test Pit (CTP) at the Idaho National Environmental and Engineering Laboratory (INEEL). The improved depth of investigation is due primarily to the development of larger loop antennas and a new transmitter capable of driving up to 30 times more current than the original transmitter into the larger loop. An overlapped antenna configuration was tried and proved effective in detecting buried objects. New display software allows us, for the first time, to generate areal time-slice displays of our data in the field for fast qualitative evaluation. Comparisons of results using two different antenna configurations over the Large Object Pit portion of the CTP show generally good agreement, but show an apparent position offset of the two data sets from each other. The test over the Calibration Cell portion of the CTP using the overlapped antenna configuration successfully located most of the indicated targets in the cell. Results over both portions of the CTP suggest that the indicated locations of some of the buried objects may not be completely accurate. New antenna and 3D forward modeling codes run using an input waveform, antenna size and configuration, and system bandwidth matching those of the VETEM system produce waveforms and show sensitivities similar to those seen in recorded field data.
Date: June 1, 1999
Creator: Wright, David L. & Chew, Weng C.
Partner: UNT Libraries Government Documents Department