Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ins respo...
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ISBN:
(纸本)0819463671
Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ins response time) infrared detectors. A farther complication arises when optical elements near the experiment are destroyed. We have designed a thermal-imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories. Inexpensive, diamond-turned, parabolic mirrors relay an image of the shocked target to the exterior of the gas gun chamber through a sapphire vacuum port. The 3000-5000-nm portion of this image is directed to an infrared camera which acquires a snapshot of the target with a minimum exposure time of 150 us. A special mask is inserted at the last intermediate image plane, to provide dynamic thermal background recording during the event. Other wavelength bands of this image are split into high-speed detectors operating at 900-1700 nm and at 1700-3000 nm, for time-resolved pyrometry measurements. This system incorporates 90-degree, off-axis parabolic mirrors, which can collect low f/# light over a broad spectral range, for high-speed imaging. Matched mirror pairs must be used so that aberrations cancel. To eliminate image plane tilt, proper tip-to-tip orientation of the parabolic mirrors is required. If one parabolic mirror is rotated 180 degrees about the optical axis connecting the pair of parabolic mirrors, the resulting image is tilted by 60 degrees. Different focal-length mirrors cannot be used to magnify the image without substantially sacrificing image quality. This paper analyzes performance and aberrations of this imaging diagnostic.
The Data Fusion Model maintained by the Joint Directors of Laboratories (JDL) Data Fusion Group is the most widely-used method for categorizing data fusion-related functions. This paper discusses the current effort to...
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ISBN:
(纸本)0819431931
The Data Fusion Model maintained by the Joint Directors of Laboratories (JDL) Data Fusion Group is the most widely-used method for categorizing data fusion-related functions. This paper discusses the current effort to revise and expand this model to facilitate the cost-effective development, acquisition, integration and operation of multi-sensor/multi-source systems. Data fusion involves combining information - in the broadest sense - to estimate or predict the state of some aspect of the universe. These may be represented in terms of attributive and relational states. If the job is to estimate the state of a people (or any other sentient beings), it can be useful to include consideration of informational and perceptual stares in addition to the physical state. Developing cost-effective multi-source information systems requires a method for specifying data fusion processing and control functions, interfaces, and associated databases. The lack of common engineering standards for data fusion systems has been a major impediment to integration and re-use of available technology: currentdevelopments do nor lend themselves to objective evaluation, comparison or re-use. This paper reports on proposed revisions and expansions of the JDL Data Fusion model to remedy some of these deficiencies. This involves broadening the functional model and related taxonomy beyond the original military focus, and integrating the Data Fusion Tree Architecture model for system description, design and development.
There is increased interest in hyperspectral imaging space missions as a powerful remote sensing technique for Earth observation. The Teledyne HgCdTe FPA and digital ROIC technology enable Teledyne e2v to provide wide...
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In this paper, we report on currentdevelopments aimed at improving the focusability of the Texas Petawatt Laser. Two major campaigns have been commissioned that address the issue of focusability. First, we implemente...
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ISBN:
(纸本)9780819484505
In this paper, we report on currentdevelopments aimed at improving the focusability of the Texas Petawatt Laser. Two major campaigns have been commissioned that address the issue of focusability. First, we implemented a closed loop, 32 actuator bi-moprh deformable mirror (DFM) to compensate for aberrations in the optical train and second, a color corrector lens assembly was installed that compensates for chromatic errors accumulated in broadband (>15 nm), large aperture (> 20 cm) laser systems. We will present in detail, pre and post correction results with the DFM and describe challenges faced when one activates a single shot, high energy closed loop system. Secondly, we will provide modeling and experimental results of our color correction system. This is a novel approach to a problem only seen in high energy, broadband, large aperture laser pulses. By using color correction optics we have demonstrated a 6X increase in focal intensity. With the installation of the DFM, the rms wavefront error in the system was reduced from 2.4 waves to. 131 waves, further increasing intensities seen at focus by 1 order of magnitude.
This paper presents the design, manufacture and electrical characterization of novel hybrid iii:V Concentrator Photovoltaic-Thermoelectric receivers. Addition of an encapsulating and spectral homogenizing single activ...
This paper presents the design, manufacture and electrical characterization of novel hybrid iii:V Concentrator Photovoltaic-Thermoelectric receivers. Addition of an encapsulating and spectral homogenizing single active surface secondary optic lens increased the solar cell electrical power output from 7.66mW (ALPHA no cooling) to 18.20mW (KAPPA with TE cooling). The effective optical concentration of the optics, based on short circuit current, was x2.4. A linear irradiance vs maximum power receiver output relationship was observed (R2=0.9978), confirming good optical alignment during manufacture and likewise internal current matching of the series-connected triple-junction cell. An in-depth COMSOL model for simulated evaluation of the synergistic thermally-dependent parameters inherent to hybrid devices was built and experimentally validated.
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