
Plasma and Ion Beam Sources
| Kaufman Source (Electrostatic Ion Thruster) | RF-Source | Microwave Source |
Features | Ø Hot cathode for electron emission | Ø 13.56 MHz RF excitation | Ø 2.45 GHz excitation, with different types of microwave antennas |
Advantages | Ø Partial Decoupling of the electron velocity distribution, and the electron density. Ø Low permanent magnetic field | Ø High plasma density (1010 to 1012 cm-3) and high radiance. Ø Long service life Ø Automatic RF adaptation possible Ø Low permanent magnetic field | Ø High plasma density (1010 to 1012 cm-3) and high radiance. Ø Long service life Ø Standard microwave adaptation. |
Disadvantages | Ø Frequent maintenance cycles due to cathode exchange. Ø Only limited operation with reactive gases. Ø Beam pollution from the cathode material. Ø High thermal stress on the substrate and the lattices due to the hot cathode excitation. Ø High electron energies and thus a higher proportion of repeatedly charged species. | Ø Capacitive coupling of the RFvoltage with the spool in the discharge must be minimized by the geometric arrangement and / or by additional Faraday shield. | Ø Static magnetic field required for ECR resonance condition. |
Technical specifications sheets:
