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Title |
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| TUPLT024 |
A Comparison of High Current Ion Beam Matching from an Ion Source to a RFQ by Electrostatic and by Magnetic Lenses
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1192 |
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- R. Becker, R.A. Jameson, A. Schempp
IAP, Frankfurt-am-Main
- T. Hata, N. Hayashizaki, H. Kashiwagi, K. Yamamoto
RLNR, Tokyo
- T. Hattori, M. Okamura, A. Sakumi
RIKEN, Saitama
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In order to improve the ?direct? injection scheme of the Riken Nd-YAK-laser driven ion source into a RFQ rf-accelerator, several basic methods have been investigated and compared, in order to transform the initially divergent ion beam into a convergent one, needed for matching the high current (100 mA C6+) ion beam at an energy of 100 keV to a RFQ. From the point of power supplies and break down characteristics, the simplest solution is a decelerating electrostatic lens, with the decelerating electrode operated on ion source potential. Due to the strong divergence of the ions beam after acceleration, this lens will be filled to an aperture, which causes strong aberrations. Therefore, we also investigated to use an accelerating potential on the lens electrode. This reduces significantly the filling of the lens and the emittance growth is only a factor of 3, as compared to the decelerating lens with a factor of 30! Finally we have been looking also into a magnetic matching system, which can match the ion beam to the RFQ with virtually no emittance growth.
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| TUPLT025 |
Matching of a C6+ Ion Beam from a Laser Ion Source to a RFQ
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1195 |
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- R. Becker, R.A. Jameson, A. Schempp
IAP, Frankfurt-am-Main
- T. Hattori
RIKEN, Saitama
- N. Hayashizaki, H. Kashiwagi
RLNR, Tokyo
- M. Okamura
RIKEN/RARF/CC, Saitama
- K. Yamamoto
RIKEN/RARF/BPEL, Saitama
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A laser ion source, driven by a Nd-YAG laser can provide more than 100 mA of C6+ ions for a duration of about 1 μs, which is well matching the task of single-turn injection into synchrotrons for hadron tumor therapy with light ions. The ?direct? injection scheme has been improved by providing a design, which reduces the surface field strength to less than 30 kV/cm on all critical parts on relative negative potential. The new design keeps the advantage of divergent ion emission and acceleration, which seems to be the only way to keep the surface fields in limits, but includes a decelerating electrostatic lens on birth potential of the ions to refocus the emerging ion beam to the RFQ entrance. The whole design is very compact and allows for electrostatic steering between the ion source and the RFQ.
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| TUPLT027 |
Status of the HITRAP Decelerator Linac at GSI
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1201 |
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- C.A. Kitegi, A. Bechtold, U. Ratzinger, A. Schempp
IAP, Frankfurt-am-Main
- T. Beier, L. Dahl, C. Kozhuharov, W. Quint, M. Steck
GSI, Darmstadt
- S. Minaev
ITEP, Moscow
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Within the European Network HITRAP (heavy Ion trap) trapped and cooled higly charged ions up to U92+ will become avilable for a variety of attractive experiments in atomic physics. Heavy ions are produced, accelerated and stripped in the GSI accelerator complex and are stored in the ESR down to 4 MeV/u. To be captured in HITRAP, ions have to be decelerated to energies below 6 keV/u. The decelerator proposed to achieve these energies is a combination of an IH Drift tube cavity operating in the H11(0) mode and a RFQ. The operating frequency is 108.408MHz . The A/q range of the linac is up to 3. A very efficient deceleration by up to 11 MV along the 2.7 m long IH cavity with a rf power of 200kw is achieved by applying the KONUS beam dynamics. The deceleration from 500 A.keV down 6A.keV is provided by a 1.8 m long 4-rod RFQ.The beam dynamics as well as the cavity design of that linac will be described.The decelerator linac will be installed in the reinjection beam line and is being developed in collaboration between GSI and the Frankfurt University .
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| TUPLT028 |
Development of Finger Drift Tube Linacs
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1204 |
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- K.-U. Kuehnel, A. Schempp
IAP, Frankfurt-am-Main
- C.P. Welsch
MPI-K, Heidelberg
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At higher particle energies the efficiency of RFQs decreases and DTL structures in combination with magnetic quadrupoles are used. One approach at IAP is the combination of RFQ and DTL. To compensate the defocusing effects of a DTL structure, the accelerating gaps of a spiral loaded cavity were equiped with small focusing fingers. These fingers arranged in a quadrupole symmetry provide an additional focusing field component. The beam dynamics of such a cavity has been studied with PARMTEQ. Simulations of the rf properties have been done using microwave studio. A prototype of a spiral loaded cavity with finger drift tubes has been built and low power measurement were made. Results of the calculations as well as low level and bead pertubation measurements are presented in this contribution.
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| TUPLT030 |
Numerical Simulations for the Frankfurt Funneling Experiment
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1210 |
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- J. Thibus, A. Schempp
IAP, Frankfurt-am-Main
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High beam currents are necessary for heavy ion driven fusion (HIF) or XADS. To achieve these high beam currents several ion beams are combined at low energies to one beam using the funneling technique. In each stage a r.f. funneling deflector bunches two accelerated beam lines to a common beam axis. The Frankfurt Funneling Experiment is a scaled model of the first stage of a HIF driver consisting of a Two-Beam RFQ accelerator and a funneling deflector. Our two different deflectors have to be enhanced to reduce particle losses during the funneling process. This is done with our new developed 3D simulation software DEFGEN and DEFTRA. DEFGEN generates the structure matrix and the potential distribution matrix with a Laplace 3D-solver. DEFTRA simulates ion beam bunches through the r.f. deflector. The results of the simulations of the two existing deflectors and proposals of new deflector structures will be presented.
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| TUPLT032 |
The Frankfurt Funneling Experiment
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1213 |
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- H. Zimmermann, U. Bartz, N. Mueller, A. Schempp, J. Thibus
IAP, Frankfurt-am-Main
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The Frankfurt Funneling Experiment is a scaled model of the first funneling stage of a HIF driver to gather experiences in the funneling technique. It is a procedure to multiply beam currents at low energies in several stages. In each stage two beam lines are combined to a common beam line. The funneling technique is required for new proposed high current accelerator facilities like HIDIF. The main goal is to prevent emittance growth during the funneling process. Our experiment consists of two ion sources, a Two-Beam RFQ accelerator, two different funneling deflectors and a beam diagnostic equipment system. We have demonstrated the principle of funneling with both deflector types. But the measurements have shown a bad matching of the RFQ to the funneling deflector. Now with our new RFQ electrode design we achieve a special three dimensional matching to the deflector. The new results of our measurements and simulations will be presented.
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| TUPLT034 |
Beam Dynamics Studies for the Low Energy Section at MAFF
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1219 |
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- M. Pasini, D. Habs, O. Kester
LMU, München
- A. Bechtold, A. Schempp
IAP, Frankfurt-am-Main
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For the LINAC of the Munich accelerator for fission fragments (MAFF) a new scheme for the low energy section has been proposed in order to fulfill new experimental requirements, such as time spacing between bunches and low longitudinal emittance. The proposed solution consists in a combination of an external multi-harmonic buncher with a "traditional" RFQ with a shaper and an adiabatic bunching section included where the employment of the external buncher is upon request from the experiment. The matching section downstream the RFQ has been re-designed in order to allow room for the installation of a beam cleaning section and to a proper injection into the following DTL. Details about the optics and beam dynamics studies of the low energy section are presented in this paper.
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| TUPLT042 |
Ring of FIRE
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1243 |
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- C.P. Welsch, J. Ullrich
MPI-K, Heidelberg
- R. Doerner, H. Schmidt-Boecking
IKF, Frankfurt-am-Main
- C. Glaessner, K.-U. Kuehnel, A. Schempp
IAP, Frankfurt-am-Main
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A small electrostatic storage ring is the central machine of the Frankfurt Ion stoRage Experiments which will be build up at the new Stern-Gerlach-Center of Frankfurt university. With ion energies up to 50 keV it will allow new methods to analyze complex many-particle systems from atoms to very large bio molecules. The high luminosity of the beam allows measurements with many orders of magnitude better resolution compared to traditional measurements. It will be combined with existing experiments, like the reaction microscope COLTRIMS and the ECR ion source. In comparison to earlier designs, the ring lattice was modified in many details: Problems in earlier designs were related with e.g. the detection of light particles and highly charged ions with different charge states. Therefore, the deflectors were redesigned completely, allowing a more flexible positioning of the diagnostics. In this contribution the final design of the storage ring is presented and the layout of all elements given. First results from vacuum measurements in the recently assembled quarter ring section are summarized.
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| THPLT041 |
Beam Test Stand of the RFQ-drifttube-combination for the Therapy Center in Heidelberg
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2568 |
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- A. Bechtold, M. Otto, U. Ratzinger, A. Schempp, E. Vassilakis
IAP, Frankfurt-am-Main
- B. Schlitt
GSI, Darmstadt
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A beam test stand for the Heidelberg medicine RFQ has been installed at the IAP in Frankfurt. The installation consists of a 8 keV/u H+ duoplasmatron ion source, the 400 keV/u RFQ itself and several diagnostic elements comprising a slit-grid emittance measurement system for scanning the transverse beam profile and a bending magnet for measuring the longitudinal beam properties. The test installation will be described in detail, first measurements will be presented and compared to corresponding beam dynamic simulations.
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