Mr. Brooks A. Childers Profile

Brooks A. Childers

R&D Manager

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Publications (17)

Proceedings Article | 11 April 2007 Paper

Downhole fiber optic real-time casing monitor

Brooks Childers, Frederick Rambow, Dennis Dria, Michelle Shuck, Daniel Homa, Stephen Poland

Proceedings Volume 6527, 65270J (2007) https://doi.org/10.1117/12.715289

KEYWORDS: Fiber Bragg gratings, Fiber optics, Cements, Hydrogen, Data modeling, Prototyping, Sensors, Temperature metrology, Spatial resolution, Reflectometry

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Proceedings Article | 27 July 2004 Paper

High-spatial-resolution temperature monitoring of an industrial motor using a distributed fiber optic sensing technique

Roger Duncan, Brooks Childers, Veera Rajendran

Proceedings Volume 5384, (2004) https://doi.org/10.1117/12.540130

KEYWORDS: Sensors, Fiber Bragg gratings, Temperature metrology, Fiber optics sensors, Optical fibers, Fiber optics, Copper, Sensing systems, Reflectometry, Failure analysis

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Proceedings Article | 10 November 2003 Paper

Use of fiber optic-based distributed temperature measurement system for electrical machines

Veera Rajendran, Mark Deblock, Todd Wetzel, Mark Lusted, Christopher Kaminski, Brooks Childers

Proceedings Volume 5191, (2003) https://doi.org/10.1117/12.504249

KEYWORDS: Temperature metrology, Sensors, Fiber optics sensors, Copper, Fiber optics, Fiber Bragg gratings, Fiber optics tests, Distributed computing, Signal processing, Spatial resolution

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A fiber optic based distributed temperature measurement system was implemented in stator windings (straight copper bars) as well as in the end-windings (curved copper bars) of a motor. Usually, in electrical machines such as motors or generators, only a few conventional temperature sensors are used, whereas the distributed temperature system has the potential of providing very detailed temperature distribution by having hundreds of sensors in a single fiber. The sensors were made of Bragg gratings etched onto the fiber itself. For the present study, the spatial resolution of the sensors is 6 mm (nominally at 1/4” apart). The technique uses Optical Frequency Domain Reflectometry (OFDR) to process the back-reflected light signal indicative of the thermal filed. A prototype fiber optic system was implemented in a motor made by GE industrial systems. The sensing length (length of the stator) for the motor was 0.75 m containing approximately 150 sensors thus providing very detailed temperature data. Performance tests were conducted at different heat loads representing different electrical conditions. Continuous tests for the duration of 19 hours were conducted. The temperature of stator windings varied from ambient (~ 23°C) to approximately 85°C. As reference, Resistance Temperature Devices (RTDs) were installed in adjacent slots to the slot where fiber optic sensors were installed. A total of 8 sensors were installed but data were collected on only 3 fibers. Fiber sensor measurements were found to track the temperature trends very well. The fiber data agreed with RTD data within ± 3°C in the entire duration. The RMS value of difference between the fiber and RTD on one side was 0.3°C, and with the RTD on the other side was 0.5°C. The fiber measurements also showed how hotspots could be missed by using few RTDs, as is done in the industry. The fiber measurements also showed the temperature distribution in the endwindings, an area not normally monitored. The maximum temperature was an acceptable 110°C. The feasibility of this technique for measuring stator-winding temperatures is proved. Still some of the problems faced during the installation and experiments are (a) robustness of fiber and sheathing fiber and (b) fiber survivability during manufacturing process and repair.

Proceedings Article | 22 July 2003 Paper

Structural integrity monitoring of aircraft panels using a distributed Bragg grating sensing technique

Dawn Gifford, Brooks Childers, Roger Duncan, Anthony Jackson, Surendra Shaw, William Schwienberg, James Mazza

Proceedings Volume 5050, (2003) https://doi.org/10.1117/12.508072

KEYWORDS: Fiber Bragg gratings, Sensors, Fiber optics sensors, Visualization, Fiber optics, Sensing systems, Optical fibers, Composites, Reflectometry, Demodulation

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Proceedings Article | 22 July 2003 Paper

Distributed sensing technique for test article damage detection and monitoring

Roger Duncan, Brooks Childers, Dawn Gifford, Don Pettit, Andrew Hickson, Timothy Brown

Proceedings Volume 5050, (2003) https://doi.org/10.1117/12.512546

KEYWORDS: Fiber Bragg gratings, Sensors, Fiber optics, Fiber optics sensors, Optical fibers, Damage detection, Nondestructive evaluation, Sensing systems, Reflectometry, Inspection

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SPIE Journal Paper | 1 October 2002

Novel piezoelectric actuators for tuning an optical fiber Bragg grating

Sidney Allison, Robert Fox, Mark Froggatt, Brooks Childers

OE, Vol. 41, Issue 10, (October 2002) https://doi.org/10.1117/12.10.1117/1.1504723

KEYWORDS: Actuators, Optical fibers, Fiber Bragg gratings, Fiber lasers, Tunable lasers, Metals, Coating, Erbium, Manufacturing, Adhesives

Proceedings Article | 14 February 2002 Paper

Recent developments in the application of optical frequency domain reflectometry to distributed Bragg grating sensing

Brooks Childers, Timothy Brown, Jason Moore, Karen Wood

Proceedings Volume 4578, (2002) https://doi.org/10.1117/12.456077

KEYWORDS: Fiber Bragg gratings, Optical fibers, Sensors, Polarization, Fiber lasers, Ultraviolet radiation, Reflectometry, Signal detection, Reflectors, Interferometers

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Proceedings Article | 14 June 2001 Paper

Use of 3000 Bragg grating strain sensors distributed on four 8-m optical fibers during static load tests of a composite structure

Brooks Childers, Mark Froggatt, Sidney Allison, Thomas Moore, David Hare, Christopher Batten, Dawn Jegley

Proceedings Volume 4332, (2001) https://doi.org/10.1117/12.429650

KEYWORDS: Fiber Bragg gratings, Composites, Fiber optics, Optical fibers, Interferometers, Sensors, Data acquisition, Calibration, Fiber optics tests, Cements

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Proceedings Article | 12 June 2000 Paper

THUNDER piezoelectric actuators as a method of stretch-tuning an optical fiber grating

Sidney Allison, Robert Fox, Mark Froggatt, Brooks Childers

Proceedings Volume 3991, (2000) https://doi.org/10.1117/12.388148

KEYWORDS: Actuators, Optical fibers, Fiber Bragg gratings, Fiber lasers, Metals, Electrodes, Smart structures, Aluminum, Erbium, Tunable lasers

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Proceedings Article | 9 July 1999 Paper

Fiber optic sensors for health monitoring of morphing aircraft

Timothy Brown, Karen Wood, Brooks Childers, Roberto Cano, Brian Jensen, Robert Rogowski

Proceedings Volume 3674, (1999) https://doi.org/10.1117/12.351590

KEYWORDS: Fiber optics, Fiber optics sensors, Fiber optics tests, Composites, Fiber Bragg gratings, Sensors, Optical fibers, Single mode fibers, Epoxies, Spectroscopy

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Proceedings Article | 31 May 1999 Paper

Characterization of a fiber Bragg grating (FBG)-based palladium tube hydrogen sensor

Yiwu Tang, Tony Peng, James Sirkis, Brooks Childers, Jason Moore, Leland Melvin

Proceedings Volume 3670, (1999) https://doi.org/10.1117/12.349766

KEYWORDS: Sensors, Hydrogen, Palladium, Fiber Bragg gratings, Nitrogen, Diffusion, Sensor performance, Aerospace engineering, Fiber optics sensors, Temperature metrology

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Proceedings Article | 18 June 1998 Paper

Integrated regenerative multicellular optical fiber grating control system

Gareth Knowles, Bruce Bower, Robert Rogowski, Leland Melvin, Brooks Childers, Sidney Allison, Leslie Cross, Ruibin Lui

Proceedings Volume 3483, (1998) https://doi.org/10.1117/12.309697

KEYWORDS: Fiber optics, Actuators, Electronics, Sensors, Fiber lasers, Optical fibers, Laser optics, Control systems design, Control systems, Optical design

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Proceedings Article | 11 November 1996 Paper

Clouds and the Earth's Radiant Energy System (CERES) instrument level 1 science data validation plan for geolocated radiances

Robert Lee, Brooks Childers, G. Louis Smith, Jack Paden, Dhirendra Pandey, Susan Thomas

Proceedings Volume 2820, (1996) https://doi.org/10.1117/12.258093

KEYWORDS: Sensors, Calibration, Space operations, Shortwaves, Clouds, Bolometers, Content addressable memory, Sensor calibration, Data modeling, Black bodies

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From spacecraft platforms, the clouds and the Earth's radiant energy system (CERES) scanning thermistor bolometers are designed to measure broadband Earth-reflected solar shortwave (0.3 - 5.0 micrometer) and Earth-emitted long wave (5.0 - greater than 100 micrometer) radiances as well as emitted longwave radiances in the 8 - 12 micrometer water vapor window over geographical footprints as small as 10 kilometers at the nadir. In ground vacuum facilities, the thermistor bolometers and in-flight blackbody and tungsten lamp calibration systems are being calibrated using radiometric sources tied to the international temperature scale of 1990 (ITS'90). Using the in-flight calibration systems, the bolometers will be calibrated periodically before and after spacecraft launch to verify the stability of the bolometers responses and to determine response drifts/shifts if they occur. The in-flight systems calibration analyses along with validation analyses will be used to determine the flight data reduction coefficients (instrument gains and offsets) which will be used to convert the bolometer measurements into calibrated radiances at the top-of-the-atmosphere (approximately 30 km). If a bolometer response shifts or drifts more than 0.5% in the longwave region or more than 1.0% in the shortwave region, and if the validation studies verify the bolometer response change, the flight data reduction coefficients will be corrected. A coastline detection method, using strong contrasting longwave ocean-land scenes, will be used to assess error limits on the geographical locations of the radiances. The detection method was successfully used to assess upper limits (6 km) on the geolocation errors for the Earth radiation budget satellite (ERBS) bolometric measurements of longwave radiances. For CERES, the detection method may be extended to shortwave radiances. In this paper, elements of the CERES instrument level 1 validation plan radiometric strategies are presented as well as the geolocation validation approaches.

Proceedings Article | 6 October 1994 Paper

Videometric system using VITC for computer-aided image management

Brooks Childers, Walter Snow, Mark Shortis

Proceedings Volume 2350, (1994) https://doi.org/10.1117/12.189148

KEYWORDS: Video, Cameras, Computing systems, Image retrieval, Image storage, Image processing, Image compression, Optical discs, Imaging systems, Binary data

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Proceedings Article | 6 October 1994 Paper

Mode shape analysis using a commercially available "peak-store" video frame buffer

Walter Snow, Brooks Childers

Proceedings Volume 2350, (1994) https://doi.org/10.1117/12.189126

KEYWORDS: Video, Cameras, Motion analysis, Photography, Shape analysis, Analog electronics, Sensors, Composites, Calibration, Analytical research

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Proceedings Article | 22 October 1993 Paper

Influence of storage media on the accuracy and repeatability of photogrammetric measurements using CCD cameras

Mark Shortis, Walter Snow, Brooks Childers, William Goad

Proceedings Volume 2067, (1993) https://doi.org/10.1117/12.162116

KEYWORDS: Video, Analog electronics, Calibration, CCD cameras, Image processing, Video processing, Digital video recorders, Cameras, Frame grabbers, Charge-coupled devices

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Proceedings Article | 24 February 1993 Paper

Recent experiences with implementing a video-based six-degree-of-freedom measurement system for airplane models in a 20-foot-diameter vertical spin tunnel

Walter Snow, Brooks Childers, Stephen Jones, Charles Fremaux

Proceedings Volume 1820, (1993) https://doi.org/10.1117/12.141379

KEYWORDS: Cameras, Video, Calibration, Systems modeling, Data acquisition, Data modeling, Lamps, Error analysis, Imaging systems, Light sources and illumination

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Showing 5 of 17 publications

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