Native fluorescence imaging direct push probe
Inventors
Boss, Pamela A. • Putnam, Michael D. • Anderson, Gregory W.
Assignees
Publication Number
US-9952156-B2
Publication Date
2018-04-24
Expiration Date
2035-06-30
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Abstract
An apparatus comprising: a direct push probe configured to be pushed into a subsurface soil environment; a transparent window mounted to a side of the probe; a white light source mounted within the probe and positioned such that when the white light source is activated only white light exits the window; an ultraviolet (UV) light source mounted within the probe and positioned such that when the UV light source is activated only UV light having a given wavelength exits the window; and an imaging system disposed within the probe and configured to capture a white-light-only-illuminated image and a UV-light-induced-fluorescence image of the subsurface soil environment at a given depth, wherein the imaging system comprises a longpass filter to filter out the UV light having the given wavelength.
Core Innovation
The invention relates to a fluorescence probe comprising a direct push probe, a transparent window mounted on the probe's side, a white light source, an ultraviolet (UV) light source, and an imaging system. The direct push probe is configured to be pushed into a subsurface soil environment, with the white light source and UV light source arranged so that light of the respective type exits through the window only when activated. The imaging system captures both a white-light-only-illuminated image and a UV-light-induced fluorescence image of subsurface soil at a given depth, employing a longpass filter to remove the UV excitation light from the fluorescence image.
The problem being addressed is that geochemical and microbiological conditions vary greatly over small distances beneath the Earth's surface, and current site characterization technologies do not effectively capture these variations. Hence, there is a need for better characterization techniques that operate effectively at smaller scales to provide real-time, in-situ imaging and assessment of subsurface soil conditions with high spatial resolution.
The fluorescence probe enables native fluorescence imaging directly within the subsurface soil by penetrating the soil to a specified depth and using controlled illumination and imaging steps. The method includes alternately illuminating the soil with white light for imaging visible features and with UV light to excite fluorescence from microbes and minerals. The resulting images are recorded in real time and superimposed to create composite images that convey microbiological activity and chemical characteristics at depth. This method allows in-situ and real-time visualization of microbial and organic matter distribution with high spatial resolution.
Claims Coverage
The patent includes multiple inventive features across six independent claims that cover innovative steps and apparatus components for fluorescence imaging in subsurface soil environments.
Use of cone penetration testing direct push probe for subsurface penetration
The method involves penetrating the subsurface soil environment to a given depth using a cone penetration testing (CPT) direct push probe, facilitating in-situ imaging.
Sequential illumination with white and UV light through a probe window
Illuminating the soil adjacent to the probe at the given depth through a window using white light and UV light separately, where UV illumination excites fluorescence in microbes and minerals.
Real-time, in-situ imaging and composite imaging creation
Recording first an image of white-light-illuminated soil and second an image of UV-light-illuminated soil after filtering out UV excitation to isolate fluorescence, then superimposing these images to produce a composite image.
Quantifying natural attenuation and assessing spatial variability
Using composite images to quantify the soil's capability to naturally attenuate contaminants, assess and manage spatial variability in geochemical and microbiological conditions, and delineate contaminants in low-permeability zones.
Use of charge-coupled device (CCD) camera for image recording
The recording of white-light and UV-light-induced fluorescence images is performed using a CCD camera capable of capturing images at appropriate spectral ranges.
Use of longpass optical filter to block UV excitation light
Filtering the UV excitation light from the fluorescence image with a longpass optical filter before the fluorescence image is recorded to ensure only fluorescence emission is captured.
Imaging at multiple depths with rapid alternating illumination
The probe is pushed to multiple depths at a location with separate composite images created at each depth, optionally with continuous pushing and rapid sequential flashes of white and UV light for imaging.
The claims collectively disclose a method and apparatus that enable detailed, real-time subsurface fluorescence imaging using a CPT direct push probe equipped with dual light sources and a specialized imaging system. This allows spatially resolved assessment and quantification of microbial and geochemical conditions and contaminant delineation in soil environments.
Stated Advantages
Provides in-situ and real-time fluorescence imaging of subsurface soil with high vertical and horizontal spatial resolution.
Enables assessment of microbial activity and organic matter distribution in the subsurface soil environment.
Allows quantification of natural attenuation capacity and management of geochemical and microbiological spatial variability.
Facilitates delineation of contaminants in low-permeability zones to guide remediation and monitoring well placement.
Documented Applications
Quantifying natural attenuation capacity of subsurface soil environments at various depths.
Assessing and managing spatial variability of geochemical and microbiological conditions underground.
Delineating contaminants, especially in low-permeability zones within subsurface soils.
Guiding remediation efforts by identifying active and inactive zones for targeted delivery of remediation agents in contaminated aquifers.
Determining optimal placement of monitoring wells and sites for further chemical sampling based on in-situ microbial and mineral fluorescence imaging.
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