Paper | Title | Page |
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THXO02 | Current Developments of the VENUS Ion Source in Research and Operations | 153 |
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The VENUS ion source functions as a research and development tool in the ECR community as well as an injector for LBNL's 88-Inch cyclotron. In order to meet the needs of both the ECR community and users at the 88-Inch cyclotron, technology such as ovens and a sputter probe have been developed for introducing metals into the plasma. Using a modified high temperature oven, VENUS has produced 450 eμA of 238U33+ and 400 eμA of 238U34+, twice the required Uranium beam current needed for FRIB. In addition, after upgrading its high voltage capabilities VENUS produced 11emA of 4He2+, a capability that remains unparalleled by other ECR ion sources. In addition to its recent record high intensities VENUS is also being developed to deliver low intensity, ultra high charge state ions for the cocktails beams, where many species are produced simultaneously for use by the BASE Facility. 124Xe43+ is now in regular production for the 16 MeV/u cocktail, and development of 209Bi56+ for the 10 MeV/u cocktail is in progress and has been accelerated through the 88-Inch cyclotron. This paper presents the latest work towards integrating the VENUS ion source into our research and operational goals. | ||
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Slides THXO02 [8.391 MB] | |
THYO03 | Design Status of ECR Ion Sources and LEBT for FRIB | 172 |
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Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams at Michigan State University is currently being designed and will provide intense beams of rare isotopes for research in nuclear physics, nuclear astrophysics and study of fundamental interactions. The FRIB driver linac will accelerate all stable isotopes from Oxygen to Uranium to energies beyond 200 MeV/u at beam powers up to 400 kW. In the case of Uranium about 13.3 pμA of U33+ are required from the ion source to reach the maximum beam power on the target. Such current is at the limit of what an ECR ion source can produce and led us to design the FRIB driver linac to accelerate concurrently two charges. The ECR ion source for FRIB will be based on the VENUS ion source developed at Lawrence Berkeley National Laboratory (LBNL). Recent beam measurements done with VENUS have demonstrated that the ion source can actually produce close to 13pμA of U33+ and therefore could possibly meet the current required for FRIB in one charge state. This paper reviews the status of the FRIB ECR ion source and the modifications that have been made to the VENUS ion source design. The Low energy beam line transport (LEBT) will also be presented and discussed. |
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Slides THYO03 [6.532 MB] | |
TUZO04 | Space Charge Compensation Measurements of Multicharged Ion Beams Extracted from an ECR Ion Source | 38 |
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Space charge compensation* due to the interaction of the beam with residual gas molecules is a well-known phenomenon for high current injector beam lines. For beam lines using mostly magnetic focusing elements and for pressure above 10-6 mbar, full neutralization has been observed. However, due to the low pressure required for the efficient transport of high charge state ions, beams in ECR injector lines are typically only partly neutralized. With the performance increase of the next generation ECR ion sources it is possible to extract tens of mA of beam current. In this high current regime, non-linear focusing effects due to the space-charge potential of the beam become more and more important. In order to develop a realistic simulation model for low energy beam transport lines, it is important to estimate the degree of space charge compensation. In this contribution we report on measurements of the beam potential (and neutralization), performed after the extraction region of the ECR ion source, in dependence of the base pressure in the beam line and other source parameters using a Retarding Field Analyzer (RFA). Results are discussed and compared to simulations.
* When the beam interacts with the residual gas, electrons are separated from gas molecules and accumulate inside the beam envelope, thereby compensating the space-charge (aka neutralization) |
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Slides TUZO04 [4.192 MB] | |