NASA Scientific and Technical Aerospace Reports

the design, operational and performance characteristics of the instrument along with a detailed description of the thickness
gauging algorithm used in the device are presented.
Derived from text
Electromagnetism; Eddy Currents; Measuring Instruments; Thickness; Conductivity
20040120913 National Renewable Energy Lab., Golden, CO
GT Reflectometer: Performance Testing/Error Analysis
Matthei, K.; Nakano, K.; 2004; In English
Report No.(s): DE2004-15006742; No Copyright; Avail: National Technical Information Service (NTIS)
Reflectance spectroscopy is very well-suited for measuring physical parameters of semiconductor wafers, and of surface
structures (continuous or patterned) deposited on them as thin films. We have developed a reflectometer (PV-Reflectometer)
that can measure physical parameters of wafers, wafer surfaces, and other materials deposited during solar cell fabrication.
Concomitantly, PV Reflectometer can also be applied for monitoring various cell fabrication processes. Specifically, this
system can monitor the following processes steps: o Wafer sawing o Texture etching o AR coating o Front metal patterning
(area and height of front metallization) o Back metallization (reflectance of back metallization). The PV Reflectometer can
measure the reflectance spectrum of an entire wafer or cell in a very short time. This spectrum is deconvolved to separate
parameters that relate to various parts of the test wafer. Recently, we have built a commercial prototype reflectometer that is
being loaned to PV Industry for evaluation and to provide feedback for fine-tuning to specific applications of each industry
partner. The PV Reflectometer has been licensed by GT Solar, Inc., Nashua, NH, for commercial production (now called GT
Reflectometer). Basic principles and the system configuration of the GT Reflectometer are described in earlier papers. Here
we will only briefly describe the system, and focus primarily on discussion of results of our investigations to assess
repeatability and error analysis. We undertook this work to establish measurement accuracies of the system and relate them
to expected ranges of variations in monitoring various processes.
NTIS
Spectroscopy; Reflectometers; Error Analysis; Reflectance
20040120932 NASA Marshall Space Flight Center, Huntsville, AL, USA
Cylindrical Asymmetrical Capacitor Devices for Space Applications
Campbell, Jonathan W., Inventor; August 10, 2004; 9 pp.; In English; Original contains black and white illustrations
Patent Info.: Filed 27 May 2003; US-Patent-6,775,123; US-Patent-Appl-SN-446282; NASA-Case-MFS-31887-1; No
Copyright; Avail: CASI; A02, Hardcopy
An asymmetrical capacitor system is provided which creates a thrust force. The system is adapted for use in space
applications and includes a capacitor device provided with a first conductive element and a second conductive element axially
spaced from the first conductive element and of smaller axial extent. A shroud supplied with gas surrounds the capacitor
device. The second conductive element can be a wire ring or mesh mounted on dielectric support posts affixed to a dielectric
member which separates the conductive elements or a wire or mesh annulus surrounding a barrel-shaped dielectric member
on which the h t element is also mounted. A high voltage source is connected across the conductive elements and applies a
high voltage to the conductive elements of sufficient value to create a thrust force on the system inducing movement thereof.
Official Gazette of the U.S. Patent and Trademark Office
Cylindrical Bodies; Capacitors; Spacecraft Electronic Equipment
20040120943 NASA Glenn Research Center, Cleveland, OH, USA
Silicon Carbide Diodes Performance Characterization at High Temperatures
Lebron-Velilla, Ramon C.; Schwarze, Gene E.; Gardner, Brent G.; Adams, Jerry; [2004]; 29 pp.; In English; Space Power
Workshop, 21 Apr. 2004, Manhattan Beach, CA, USA
Contract(s)/Grant(s): WBS 319-20-N1; No Copyright; Avail: CASI; A03, Hardcopy
NASA Glenn Research center’s Electrical Systems Development branch is working to demonstrate and test the
advantages of Silicon Carbide (SiC) devices in actual power electronics applications. The first step in this pursuit is to obtain
commercially available SiC Schottky diodes and to individually test them under both static and dynamic conditions, and then
compare them with current state of the art silicon Schottky and ultra fast p-n diodes of similar voltage and current ratings. This
presentation covers the results of electrical tests performed at NASA Glenn. Steady state forward and reverse current-volt
(I-V) curves were generated for each device to compare performance and to measure their forward voltage drop at rated
current, as well as the reverse leakage current at rated voltage. In addition, the devices were individually connected as
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