Sputter ion source
With a sputter ion source , particles are accelerated towards a target , where they knock out atoms of the material (see sputtering ) and ionize them . These ions are then extracted by electrical fields and form an ion beam , for example for a particle accelerator .
functionality
In its most common form, cesium is used as an auxiliary material. A furnace heats cesium to ≈ 120 ° C. The resulting cesium vapor reaches the source space and fills it. Part of the vapor condenses on the cooled sputtering target (the cathode ) and forms a layer on the surface there. The sputter target consists of a chemical compound or the pure element that is desired for the ion beam. It is usually pressed into a copper mold. Another part of the steam comes into contact with the ionizer . The hemispherical ionizer (mostly made of tungsten and tantalum ) is heated to ≈ 1000 ° C. The striking cesium atoms are ionized and accelerated towards the sputtering cathode by a potential difference ( electrical voltage ) of approximately 6 kV between the ionizer and the cathode . There different atoms and ions of the target material are knocked out of the surface . The ions relevant for the beam take up electrons with a certain probability as they pass through the cesium layer on the surface and are then present as negatively charged ions. The ions are then accelerated away from the source by the existing potential difference.
Web links
- Negative Ion Beam Sources . National Electrostatics Corporation, accessed March 2, 2011.
- Sputter ion source . Helmholtz-Zentrum Dresden-Rossendorf, accessed March 2, 2011.