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Two Fiber Optical Fiber ThermometryAn optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber is essentially an isothermal cavity, so the emission from this cavity will be approximately equal to the emission from a blackbody. Temperature readings are obtained by measuring the spectral radiative heat flux at the end of the fiber at two wavelengths. The ratio of these measurements and Planck's Law are used to infer the temperature at the sensing tip. Optical fiber thermometers have high accuracy, excellent long-term stability and are immune to electromagnetic interference. In addition, they can be operated for extended periods without requiring re-calibration. For these reasons. it is desirable to use optical fiber thermometers in environments such as the International Space Station. However, it has recently been shown that temperature readings are corrupted by emission from the fiber when extended portions of the probe are exposed to elevated temperatures. This paper will describe several ways in which the reading from a second fiber can be used to correct the corrupted temperature measurements. The accuracy and sensitivity to measurement uncertainty will be presented for each method.
Document ID
20000033985
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Jones, Mathew R.
(Arizona Univ. United States)
Farmer, Jeffery T.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Breeding, Shawn P.
(Tec-Masters, Inc. United States)
Date Acquired
August 19, 2013
Publication Date
January 25, 2000
Subject Category
Instrumentation And Photography
Meeting Information
Meeting: Mechanical Engineering
Location: Orlando, FL
Country: United States
Start Date: November 5, 2000
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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