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.