Scanning optical pyrometer for measuring temperatures in hollow cathodes.

Area of Science:

• Physics
• Materials Science
• Engineering

Background:

• Hollow cathode performance and lifespan are significantly influenced by the electron emitter's temperature.
• Accurate temperature measurement is crucial for predicting cathode longevity and optimizing operational parameters.

Purpose of the Study:

• To develop and validate a noncontact temperature measurement technique for hollow cathodes.
• To enable precise assessment of electron emitter temperature profiles for life-limiting process analysis.

Main Methods:

• A stepper motor-driven fiber optic probe was engineered to navigate the interior of the hollow cathode.
• Ratio pyrometry was employed to analyze the emitted light and determine the axial temperature profile.
• In situ calibration was performed using thermocouples and an external heating oven to ensure measurement accuracy.

Main Results:

• The developed diagnostic method successfully measured the axial temperature distribution within the hollow cathode.
• Initial measurements provided insights into the thermal behavior of the electron emitter during operation.

Conclusions:

• The noncontact fiber optic probe and ratio pyrometry system offer a viable method for internal hollow cathode temperature diagnostics.
• This technique supports improved cathode life assessment and operational management by providing critical thermal data.