Characterisation of thermionic emission current with a laser-heated system

Area of Science:

• Materials Science
• Surface Science
• Physics

Background:

• Thermionic emission is crucial for electron guns, X-ray sources, and thermionic energy converters.
• Developing and testing novel thermionic materials requires reliable and repeatable methods.
• Existing testing methods can be limited by material optical properties or form factor.

Purpose of the Study:

• To present a versatile CO2 laser-heated system for thermionic emission testing.
• To enable reliable and repeatable characterization of thermionic materials.
• To demonstrate the system's capability across different materials and temperatures.

Main Methods:

• Utilized a CO2 laser heating system capable of reaching sample temperatures of approximately 1000°C.
• Implemented pre-programmed heating profiles for controlled temperature variations.
• Incorporated a double thermo-electrical decoupling mechanism to minimize electrical noise and heat loss.
• Tested hydrogen-terminated single-crystal diamond samples.

Main Results:

• The system successfully reached and maintained sample temperatures up to 1000°C.
• Demonstrated the ability to test thermionic emission current irrespective of material optical properties or form factor.
• Obtained experimental data on sample temperature and thermionic current for diamond samples.
• The double thermo-electrical decoupling effectively reduced electrical noise.

Conclusions:

• The developed CO2 laser-heated system provides a reliable and versatile platform for thermionic material testing.
• The system's design allows for accurate characterization of thermionic properties across diverse materials.
• The methodology is suitable for evaluating new materials and surface functionalizations for thermionic applications.