Contrib. Plasma Phys. 47, No. 7, 487 – 497 (2007) / DOI 10.1002/ctpp.200710063 Broad Beam Ion Sources for Electrostatic Space Propulsion and Surface Modification Processes: From Roots to Present Applications H. Neumann ∗1 , M. Tartz 1 , F. Scholze 1 , T. Chass´ e 2 , H. Kersten 3 , and H. Leiter 4 1 Leibniz - Institut f¨ ur Oberfl¨ achenmodifizierung e.V., Permoserstraße 15, D-04318 Leipzig, Germany 2 Universit¨ at T¨ ubingen, Institut f¨ ur Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 T¨ ubingen, Germany 3 Christian-Albrechts-Universit¨ at zu Kiel, Institut f¨ ur Experimentelle und Angewandte Physik, Leibnizstraße 11-19, D-24098 Kiel, Germany 4 Astrium Space Transportation GmbH, Langer Grund, D-74239 Hardthausen-Lampoldshausen, Germany Received 7 March 2007, accepted 28 September 2007 Published online 5 November 2007 Key words Broad beam ion sources, electrostatic ion thruster, Faraday cup measurements, mass spectrometry, thermal probe, micro-disperse particles, ion beam profile control, multilayer, ion beam modelling. PACS 52.75.Di, 52.40.Hf, 52.59.Bi, 52.65.Ce, 07.77.Ka, 41.75.Ak Ion thrusters or broad beam ion sources are widely used in electrostatic space propulsion and in high-end surface modification processes. A short historical review of the roots of electric space propulsion is given. In the following, we introduce the electrostatic ion thrusters and broad beam ion sources based on different plasma excitation principles and describe the similarities as well as the differences briefly. Furthermore, an overview on source plasma and ion beam characterisation methods is presented. Apart from that, a beam profile modelling strategy with the help of numerical trajectory codes as basis for a special grid system design is outlined. This modelling represents the basis for the adaptation of a grid system for required technological demands. Examples of model validation demonstrate their reliability. One of the main challenges in improvement of ion beam technologies is the customisation of the ion beam properties, e.g. the ion current density profile for specific demands. Methods of an ex-situ and in-situ beam profile control will be demonstrated. Examples for the use of ion beam technologies in space and on earth – the RIT-10 rescue mission of ESA’s satellite Artemis, the RIT-22 for BepiColombo mission and the deposition of multilayer stacks for EUVL (Extreme Ultra Violet Lithography) mask blank application are provided in order to illustrate the potential of plasma-based ion beam sources. c  2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 Roots and Introduction In 1886 the German physicist Eugen Goldstein discovered for the first time positive charge carriers behind a slotted cathode of a DC gas discharge (30kV, Neon) in a vacuum tube and named this beamlike phenomenon ”Kanalstrahlen”. Not until thirty years later these beams (”Kanalstrahlen”) could be interpreted as consisting of positively charged atoms – the ions. This conclusion was possible after the postulation of the atomic model by E. Rutherford. In the following time some different types of ion sources for a lot of applications were developed, e.g. particle accelerators (cyclotron: E. Lawrence in 1929), analytical equipments (mass spectroscopy), isotope separators and ion implanters. The broad beam ion source technology was driven by the electric space propulsion started in the era of vi- sionaries (1906-1945: Tsiolkovsky [1], Goddard [2], and Obert [3] ) followed by the era of pioneers (1946-1956: ∗ Corresponding author: e-mail: horst.neumann@iom-leipzig.de c  2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim