| Paper | Title | Page |
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| MOP05 | The HITRAP-Decelerator for Heavy Highly-Charged Ions | 39 |
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| The GSI accelerator facility provides highly charged ions up to U92+ by stripping the ions at 400 MeV/u in the transfer line from the SIS18 (Heavy Ion Synchrotron) to the ESR (Experimental Storage Ring). The ESR provides high quality beams by means of stochastic cooling and electron cooling. Deceleration down to 4 MeV/u was already successfully demonstrated. After suitable rebunching, further deceleration down to 6 keV/u, neccessary for the capture of the ions by a penning trap, is done by IH/RFQ-structures. All cavities are operated at 108 MHz. Recently the HITRAP-project (Heavy Ion Trap), described in a Technical Design Report, was approved. The layout of the decelerator and the beam dynamics in different sections are reported. | ||
| MOP06 | A Dedicated 70 MeV Proton Linac for the Antiproton Physics Program of the Future Facility for Antiproton and Ion Research (FAIR) at Darmstadt | 42 |
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| The antiproton physics program of the future International Accelerator Facility at Darmstadt is based on a rate of 7·1010 cooled antiprotons per hour. To provide the primary proton intensities a proton linac is planned, which will be operated independently from the existing UNILAC for heavy ions. The proposed linac comprises a proton source, a RFQ, and a DTL. Its operation frequency of 352 MHz allows for an efficient acceleration to up to 70 MeV using normal conducting Crossed-bar H-cavities. These CH-cavities show high shunt impedances as known from IH-structures, but allow for much higher relative particle velocities of up to 40%. The beam pulses with a length of 25 μs, a current of 70 mA, and total transverse emittances of 7 μm will allow to fill the existing synchrotron SIS within one multi-turn-injection up to its space charge limit of 7·1012 protons. The maximum SIS ramping rate limits the applied proton linac repetition rate to 5 Hz. This paper gives an overview of the proposed proton linac. The status of the design including beam dynamic studies will be reported. | ||
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Transparencies | |
| MOP09 | Status of the 7 MeV/u, 217 MHz Injector Linac for the Heidelberg Cancer Therapy Facility | 51 |
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A clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany, starting in 2005. The status of the ECR ion source systems, the beam line components of the low energy beam transport lines, the 400 keV/u RFQ and the 20 MV IH-cavity as well as the linac rf system will be reported. Two prototype magnets of the linac quadrupole magnets have been built at GSI and have been tested successfully. A test bench for the 1.4 MW, 217 MHz cavity amplifier built by industry has been installed at GSI including a 120 kW driver amplifier which will be used also for high power tests of the RFQ. A test bench for the RFQ using proton beams is presently being set up at the IAP. RF tuning of the 1:2 scaled IH-DTL model as well as Microwave Studio simulations of the model and the power cavity have been also performed at the IAP [1].
[1] Y.Lu, S.Minaev, U.Ratzinger, B.Schlitt, R.Tiede, this conference. |
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Transparencies | |
| MOP10 | The IH Cavity for HITRAP | 54 |
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| RFQs are already successfully used to decelerate ions and to match them to ion traps. Within the Heavy Ions TRAP project HITRAP at GSI a combination of an IH drift tube cavity operating at the H11(0) mode and a 4-rod RFQ is proposed to decelerate the 1 ms long heavy ion bunches (up to U92+) from 4 A×MeV to 6 A keV after storage ring extraction. The transition energy from the IH into the RFQ is 0.5AmeV. The operating frequency is 108.408 MHz. The A/q range of the linac is up to 3.A 4-gap quarter wave resonator working at 108.408MHz provides theμbunch structure for the IH. The transmission mainly defined by the buncher is about 30%. An alternative 2nd harmonic bunching section, which allows higher transmission and/or smaller longitudinal emittance, will be discussed.By applying the KONUS dynamics, the 2.7 meter long IH cavity will perform a high efficient deceleration by up 10.5 MV with 200kW rf power. The beam dynamics performed with the LORASR simulation code will be shown. It is aimed to reach an effective shunt impedance around 220MW/m for the IH cavity | ||
| MOP11 | The Compact 20 MV IH-DTL for the Heidelberg Cancer Therapy Facility | 57 |
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| A clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany, starting in 2005. The different rf tuning concepts and tuning results for an 1:2 scaled IH-DTL model cavity are presented. Microwave Studio simulations have been carried out for the model and for the real power cavity. Results from the model measurements and the field simulations agree very well also for the higher order modes. The beam matching from the RFQ to the IH-DTL was optimised. Beam dynamics simulations using the LORASR code and starting with a particle distribution at the RFQ exit as calculated with PARMTEQ are presented. The IH drift tube array was matched with the gap voltage distribution resulting from rf model measurements. | ||
| MOP12 | KONUS Beam Dynamics Design of a 70 mA, 70 MeV Proton CH-DTL for GSI-SIS12 | 60 |
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| The future scientific program at GSI needs a dedicated proton injector into the synchrotron SIS, in order to increase the proton intensity of the existing UNILAC/SIS12 combination by a factor of 70, resulting in 7· 1012 protons in the synchrotron. A compact and efficient 352 MHz RFQ - CH-DTL combination based on novel structure developments for RFQ and DTL was worked out. For DTLs operated in an H-mode like CH-cavities (H210-mode), the shunt impedance is optimized by use of the KONUS beam dynamics. Beam dynamics simulation results of the CH-DTL section, covering the energy range from 3 to 70 MeV, with emphasis on the low energy front end are presented. Optimization aims are the reduction of emittance growth, of beam losses and of capital costs, by making use of the high acceleration gradients and shunt impedance values provided by the Crossbar H-Type (CH) structure. In addition, the beam dynamics design of the overall DTL layout has to be matched to the power limits of the available 352 MHz power klystrons. The aim is to power each cavity by one klystron with a peak rf power of around 1 MW. | ||
| MOP20 | Design of the R.T. CH-Cavity and Perspectives for a New GSI Proton Linac | 81 |
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| The CH-Structure has been studied at the IAP Frankfurt and at GSI for several years. Compared with the IH structure (H110-mode), the CH structure (H210-mode) can work at higher frequency (700 MHz) and can accelerate ions to higher energy (up to 150 AMeV). Detailed Microwave Studio (MWS) simulations were performed for this structure. Since a multi-gap cavity can be approximated as a quasi-periodic structure, it is possible to analyze one βλ/2-cell at an energy corresponding to the cavity center. Additionally, a reduced copper conductivity of 85% was assumed. Geometry variations with respect to rf frequency and shunt impedance can be performed rapidly by that method in the first stage of optimization. Effective shunt impedances from 100 MΩ/m down to 25 MΩ/m were obtained for the energy range from 5 AMeV to 150 AMeV by this method. The rf frequency was 350 MHz up to 70 MeV and 700 MHz above. A systematic analysis of the influence of the cell number in long CH cavities on the effective shunt impedance is presented. The possibility to apply this structure to a 70 mA, 70 MeV, 352 MHz proton linac for GSI is discussed. | ||
| TUP82 | Low Energy Beam Transport using Space Charge Lenses | 465 |
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| Gabor lenses provide strong cylinder symmetric electric focusing using a confined nonneutral plasma. The density distribution of the enclosed space charge is defined by the enclosure conditions in transverse and longitudinal direction. For a homogeneous charge density distribution the resulting electrostatic field and therefrom the focusing forces inside the space charge cloud are linear. Additionally in case of a positive ion beam the space charge of the confined electrons causes compensation of the ion beam space charge forces. To study the capabilities of a Gabor double lens system to match an ion beam into a RFQ a testinjector was installed at the IAP and put into operation successfully. First beam profiles and emittance measurements as well as measurements of the beam energy and energy spread have already been performed and show satisfactory results and no significant deviation from the theoretical predictions. To verify the beam focusing of bunched beams using this lens type at beam energies up to 500 keV a new high field Gabor lens was build and will be installed behind of the RFQ. | ||
| TUP86 | Coupler Development and Gap Field Analysis for the 352 MHz Superconducting CH-Cavity | 477 |
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| The cross-bar H-type (CH) cavity is a multi-gap drift tube structure based on the H-210 mode currently under development at IAP Frankfurt and in collaboration with GSI. Numerical simulations and rf model measurements showed that the CH-type cavity is an excellent candidate to realize s.c. multi-cell structures ranging from the RFQ exit energy up to the injection energy into elliptical multi-cell cavities. The reasonable frequency range is from about 150 MHz up to 800 MHz. A 19-cell, β=0.1, 352 MHz, bulk niobium prototype cavity is under development at the ACCEL-Company, Bergisch-Gladbach. This paper will present detailed MicroWave Studio simulations and measurements for the coupler development of the 352 MHz superconducting CH cavity. It will describe possibilities for coupling into the superconducting CH-Cavity. The development of the coupler is supported by measurement on a room temperature CH-copper model. We will present the first results of the measurements of different couplers, e.g. capacitive and inductive couplers, at different places of the CH Cavity. |