Lanthanum hexaboride hollow cathode for dense plasma production

Area of Science:

• Materials Science
• Plasma Physics
• Vacuum Technology

Background:

• Electron emitters are crucial components in various vacuum and plasma devices.
• Lanthanum hexaboride (LaB6) is known for its high electron emission properties.
• Developing robust and long-lasting cathodes is essential for sustained high-current applications.

Purpose of the Study:

• To design and construct a novel hollow tube cathode utilizing lanthanum hexaboride (LaB6).
• To evaluate the performance characteristics and operational stability of the LaB6 cathode.
• To assess the potential lifetime and durability of the developed cathode under various conditions.

Main Methods:

• A hollow tube cathode was designed and fabricated using lanthanum hexaboride as the electron emitter.
• Performance tests were conducted in argon and hydrogen environments.
• Emission current density, operational stability, and durability (including air exposure) were measured.

Main Results:

• The LaB6 cathode continuously produced over 800 A of electron current.
• Achieved emission current density exceeded 25 A/cm² from the LaB6 surface.
• The cathode demonstrated stable operation for over 300 hours and withstood over 100 air exposures without emission degradation.
• Projected lifetime for the sintered LaB6 component exceeds 3500 hours.

Conclusions:

• The designed hollow tube LaB6 cathode is a highly capable electron source for demanding applications.
• The cathode exhibits exceptional emission current, stability, and durability, suggesting a long operational lifespan.
• Further investigation into space charge effects can optimize emission performance.