Paper |
Title |
Page |
WEYO03 |
Ion Beam Extraction from Magnetized Plasma |
106 |
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- P. Spädtke, R. Lang, J. Mäder, F. Maimone, J. Roßbach, K. Tinschert
GSI, Darmstadt, Germany
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With increasing the total extracted current for any ion source, the optimisation of the extraction system becomes more important, because of the space charge effect. Several attempts have been made in the past to simulate the extraction from an Electron Cyclotron Resonance Ion Source (ECRIS) in a correct way. Most of these attempts failed, because they were not able to reproduce the experimental results. The best model up to now is given by the following procedure: tracing the magnetic field lines through the extraction aperture, looking where these field lines are coming from; using these coordinates of the magnetic field line as starting points for ions to be extracted; the initial current of each trajectory is determined by theoretical assumptions about the plasma or by a plasma simulation; Child's law is applicable locally only in direction of the magnetic field, if no emission limited flow is present.
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Slides WEYO03 [16.955 MB]
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WEPP15 |
Metal Ion Beam Production with Improved Evaporation Ovens |
140 |
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- K. Tinschert, R. Lang, J. Mäder, F. Maimone, J. Roßbach
GSI, Darmstadt, Germany
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Most of the ion beams delivered by the ECR ion sources at the GSI accelerator facilities are produced from materials in the solid state, which must be transformed into the gaseous state to feed the plasma. The well established method of thermal evaporation has been used by means of two types of resistively heated ovens for metals and solid compounds. The main goal of development is to improve their versatility in terms of lifetime, durability, efficiency, and extended temperature range. Recent investigations and developments include the use of alternative materials for oven components. The main focus has been on the further development of the high temperature oven. A modular construction with improved mechanical dimensional accuracy for more precise and easier mounting has been established. Its optimization for stable long time operation has been continued leading to a lifetime of 6 days for evaporation of Ti at 1750°C. Furthermore the temperature limit could be extended to 2300°C. In addition to the improvements in evaporation technology the technique of microwave frequency tuning could be successfully applied for metal ion operation leading to enhanced ion beam intensities.
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