Hollow cathode effect
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The hollow cathode effect allows electrical conduction at a lower voltage or with more current in a cold-cathode gas-discharge lamp when the cathode is a conductive tube open at one end than a similar lamp with a flat cathode.cite-ref-eichhornschoenbach1993-1-0[1] The hollow cathode effect was recognized by Friedrich Paschen in 1916.cite-ref-paschen1916-2-0[2]
In a hollow cathode, the electron emitting surface is in the inside of the tube. Several processes contribute to enhanced performance of a hollow cathode:
• The pendulum effect, where an electron oscillates back and forth in the tube, creating secondary electrons along the way
• The photoionization effect, where photons emitted in the tube cause further ionization
• Stepwise ionizationcite-ref-eichhornschoenbach1993-1-1[1]
The hollow cathode effect is utilized in the electrodes for neon signs, in hollow-cathode lamps, and more.
References
cite-note-eichhornschoenbach1993-11. ↑ citerefeichhornschoenbachtessnow1993Eichhorn, H.; Schoenbach, K. H.; Tessnow, T. (1993). "Paschen's law for a hollow cathode discharge" (PDF). Applied Physics Letters. 63 (18): 2481–2483. Bibcode:1993ApPhL..63.2481E. doi:10.1063/1.110455. ISSN 0003-6951. Archived from the original (PDF) on August 8, 2017. Retrieved June 5, 2017.