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Scanning optical pyrometer for measuring temperatures in hollow cathodes

Polk, J. E. and Marrese-Reading, C. M. and Thornber, B. and Dang, L. and Johnson, L. K. and Katz, I. (2007) Scanning optical pyrometer for measuring temperatures in hollow cathodes. Review of Scientific Instruments, 78 (9). Art. No. 093101. ISSN 0034-6748. doi:10.1063/1.2774828.

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Life-limiting processes in hollow cathodes are determined largely by the temperature of the electron emitter. To support cathode life assessment, a noncontact temperature measurement technique which employs a stepper motor-driven fiber optic probe was developed. The probe is driven inside the hollow cathode and collects light radiated by the hot interior surface of the emitter. Ratio pyrometry is used to determine the axial temperature profile. Thermocouples on the orifice plate provide measurements of the external temperature during cathode operation and are used to calibrate the pyrometer system in situ with a small oven enclosing the externally heated cathode. The diagnostic method and initial measurements of the temperature distribution in a hollow cathode are discussed.

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Additional Information:©2007 American Institute of Physics. (Received 4 May 2007; accepted 31 July 2007; published online 10 September 2007) The authors wish to thank Al Owens and Ray Swindlehurst for their assistance in the design and fabrication of the apparatus for this experiment. The research described in this article was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration in support of Project Prometheus.
Subject Keywords:calibration; fibre optic sensors; pyrometers; temperature distribution; temperature measurement; thermionic cathodes; thermocouples
Issue or Number:9
Record Number:CaltechAUTHORS:POLrsi07
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8778
Deposited By: Archive Administrator
Deposited On:15 Sep 2007
Last Modified:08 Nov 2021 20:53

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