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Title |
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MOP032 |
Upgrade of the Unilac High Current Injector RFQ
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136 |
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- A. Kolomiets, S. Minaev
ITEP, Moscow
- W. Barth, L.A. Dahl, H. Vormann, S. Yaramyshev
GSI, Darmstadt
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Funding: Work supported by the European Community INTAS Project Ref. no. 06-1000012-8782.
For the operation of the GSI-accelerator chain as an injector for the future FAIR facility a considerable increase of the heavy ion beam intensity by a factor 3-5 at the end of the UNILAC is required. The bottleneck of the whole UNILAC, is the front-end system of the High Current Injector. It is shown that the transverse RFQ-acceptance can be significantly increased while the emittance growth can be reduced. Both goals are achieved with only a moderate change of the RFQ electrode geometry; the intervane voltage raised from 125 kV to 155 kV keeping the design limit of the maximum field at the electrode surface. The changed resonant frequency can be compensated with a relatively small correction of the carrying rings. The beam parameters in the final focusing elements of the LEBT were improved together with the input radial matcher design; the length of the gentle buncher section was considerably increased to provide slow and smooth bunching resulting in a reduce influence of space charge forces. DYNAMION-simulation with the modified electrode design resulted in an increase of U4+-beam current of up to 20 emA. It is planned to start the upgrade measure in spring 2009.
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MOP057 |
Linac Front-End Upgrade at the Cancer Therapy Facility HIT
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208 |
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- M.T. Maier, W. Barth, A. Orzhekhovskaya, B. Schlitt, H. Vormann, S. Yaramyshev
GSI, Darmstadt
- R. Cee
HIT, Heidelberg
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A clinical facility for cancer therapy using energetic proton and ion beams (C, He and O) has been installed at the Radiologische Universitätsklinik in Heidelberg, Germany. It consists of two ECR ion sources, a 7 MeV/u linac injector, and a 6.5 Tm synchrotron to accelerate the ions to energies of 430 MeV/u. The linac comprises a 400 keV/u RFQ and a 7 MeV/u IH-DTL operating at 216.8 MHz and has been commissioned successfully in 2006. Yet the overall achieved transmission through the injector linac did not exceed 30% due to a mismatch of the beam at the RFQ entrance. Thus a detailed upgrade programme has been started to exchange the RFQ with a new radial matcher design, to correct the alignment and to optimize beam transport to the IH-DTL. The aim is to achieve a sufficient linac transmission above 60%. The new design of the RFQ has been finished in 2007 and the RFQ is currently in production. A test bench comprising a full ion source and LEBT setup to commission the RFQ in 2008 is under construction at Danfysik in Danemark. The current status of this upgrade programme will be reported in this contribution.
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MOP075 |
Benchmarking of Measurement and Simulation of Transverse RMS-Emittance Growth Along an Alvarez DTL
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251 |
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- L. Groening, W. Barth, W.B. Bayer, G. Clemente, L.A. Dahl, P. Forck, P. Gerhard, I. Hofmann, G.A. Riehl, S. Yaramyshev
GSI, Darmstadt
- D. Jeon
ORNL, Oak Ridge, Tennessee
- D. Uriot
CEA, Gif-sur-Yvette
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Funding: CARE, contract number RII3-CT-2003-506395) European Community INTAS Project Ref. no. 06-1000012-8782
Transverse emittance growth along the Alvarez DTL section is a major concern with respect to the preservation of beam quality of high current beams at the GSI UNILAC. In order to define measures to reduce this growth appropriate tools to simulate the beam dynamics are indispensable. This paper is on benchmarking of three beam dynamics simulation codes, i.e. DYNAMION, PARMILA, and PARTRAN against systematic measurements of beam emittance growth for different machine settings. Experimental set-ups, data reduction, the preparation of the simulations, and the evaluation of the simulations will be described. It was found that the mean value of final horizontal and vertical rms-emittances can be reproduced well by the codes.
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