Plasma-Anode Electron Gun Research
Abstract
The plasma-anode electron gun (PAG) is a new cold-cathode electron source which exhibits many novel features. These include instant starting, no cathode heater power, minimal vacuum requirements, a nonpoisoning cathode, long- pulse operation without gap closure, and beam modulation at ground potential with constant beam energy. The basic concept involves a collective interaction between counterpropagating streams of electrons and ions in a high-voltage diode gap. A Pierce electron-gun configuration is employed, but the thermionic cathode is replaced with a cold, secondary-electron-emitting electrode. Electron emission is stimulated by bombarding the cathode with high-energy ions. The ions are injected into the high-voltage gap through a gridded structure from a plasma source, which is embedded inside the anode electrode. The gridded structure serves as both a cathode for the plasma discharge and as an anode for the PAG. As high-voltage ions impact the cathode surface, secondary electrons are emitted, accelerated back through the diode gap, and focused through an on-axis aperture in the anode. Under this program, a modified Herrmannsfeldt computer code was constructed that calculates electron and ion trajectories and limiting particle currents in realistic geometries in the self-consistent space-charge fields of both particle species.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 1989
- Accession Number
- ADA211547
Entities
People
- Joseph Santoru
- Robert W. Schumacher
Organizations
- HRL Laboratories