| Paper | Title | Page |
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| MOPCH109 | Design Studies on a Novel Stellarator Type High Current Ion Storage Ring | 297 |
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| A high current storage ring for the accumulation of ion beams provided by a new 150 kV terminal is under consideration at the Frankfurt University. The configuration based on a toroidal magnetic field seems promising for the storage of intense low energy ion beams, especially when concerning the various potential concepts for space charge compensation. The theory of plasma confinement on magnetic surface is transformed to numerical simulations on circulating ion beams. The space charge effects and stability conditions are studied and will be presented. Various injection techniques based on crossed field-drifts are investigated. Accordingly test experiments are prepared based on two 30 degree toroidal sectors at a major radius of 1.3m with a maximum toroidal magnetic field of 0.6T on axis. | ||
| MOPCH153 | Peak Field Optimization for the Superconducting CH Structure | 415 |
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| The Cross-Bar H-type (CH) cavity is a multi-gap drift tube structure operated in the H-210 mode which has been developed at the IAP Frankfurt and in collaboration with GSI. Based on detailed numerical simulations a 19 cell prototype cavity from massive Nb was realised. For optimization of the magnetic and electric peak fields, detailed numerical simulations with CST MicroWave Studio have been performed. After successful experiments on the superconducting prototype cavity calculations about improved drift tube geometries with respect to field emission took place. Additionally, the stem geometry was further improved by simulations. | ||
| TUPCH115 | Status of the 70 MeV, 70 mA CH Proton-DTL for FAIR | 1283 |
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| The CH-type cavity shows promising features in the low and medium beta range: its high accelerator gradient and the high level of shunt impedance together with the compact transverse dimensions make this new cavity a good candidate for proton acceleration up to 100 MeV. That's why GSI has decided to base the new high current proton injector for the new FAIR facility on that structure: the operating frequency will be 352 MHz with an injection energy of 3 MeV. In order to improve the technical experience on this new kind of structure, IAP has built a model consisting of 8 equidistant gaps for a total cavity-length of 60 cm. Several design options with respect to welding, alignement, cooling and RF joints were studied and compared each other. A new concept for the end-cells geometry will result in the desired flatness of the electric field along the cavity axis and, at the same time, allow effective integration of internal quadruple lenses. Finally, the electric quadruple content of CH-structure gaps is listed in dependence on the geometry of the cell. | ||
| TUPLS034 | UNILAC Upgrade Programme for the Heavy Element Research at GSI-SHIP | 1565 |
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| In the field of heavy-element research using the velocity separator SHIP significant achievements were made at GSI during the last 30 years. The experiences obtained of experiments clearly show that superheavy-element research was always based on efforts to extend the limits of technical possibilities - of these the increase of beam intensity is one of the major contributions. This paper provides for technical information on the already planned upgrades of the present facility, which results in a significant overall increase of the experimental sensitivity. It is foreseen to investigate and to build a sc 28 GHz-ECR ion source, which should increase the primary beam intensities. The beam coming from the new ECR source will be delivered to the GSI-High Charge State Injector by a second LEBT-system. An upgrade program for the rf-amplifiers and the rf-structures is intended to increase the duty factor from 30 % to 50 %. Besides the ECR-source a new RFQ accelerator and the IH structure may alternatively serve as an injector for an new advanced stand alone accelerator providing for 100 % duty factor. Two different linac-layouts will be discussed. | ||
| TUPLS035 | The HITRAP Decelerator Project at GSI | 1568 |
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| The heavy ion trap (HITRAP) at GSI is a funded project since 2004. Highly charged ions up to U92+ provided by the GSI accelerator facility will be decelerated and subsequently injected into a Penning trap for further cooling almost to rest. A combination of an IH- and an RFQ-structure decelerates the ions from 4 MeV/u down to 6 keV/u. In front of the decelerator a double-drift-buncher-system provides for phase focusing and a final debuncher integrated in the RFQ-tank reduces the energy spread in order to improve the efficiency for beam capture in the cooler trap. The report gives an overview of the final beam dynamic design of the entire decelerator. Besides the construction status of the cavities, particular beam diagnostic features due to the short pulses of 1 μs and 108 MHz bunch frequency, and the measures for technical and controls integration into the existing GSI accelerator complex are presented. Finally the recent time schedule and considerations for commissioning are shown. | ||
| TUPLS038 | The MAFF IH-RFQ Test Stand at the IAP Frankfurt | 1577 |
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| The IH-type RFQ for the MAFF project at the LMU in Munich is presently under construction and will be integrated into a beam test stand at the IAP in Frankfurt. It is the second RFQ following the IH resonator concept and the first one that can be directly compared to a very similar 4-rod type machine, namely the REX-ISOLDE RFQ at CERN. The MAFF RFQ has been designed to accelerate rare isotope beams (RIBs) with mass to charge ratios up to 6.3 from 3 keV/u to 300 keV/u at an operating frequency of 101.28 MHz with an electrode voltage of 60 kV. First RF-measurements have already been executed and can be compared to appropriate simulation results. Parts of the test stand are currently under construction, such as the volume ion source for He+ at an extraction voltage of 12 keV and an electrostatic quadruplet for injection with an integrated steering system. These tests and accompanying theoretical investigations will be done with special respect to the applicability of such normal conducting RFQ accelerators to the EURISOL post accelerator. | ||
| TUPLS042 | First Cryogenic Tests of the Superconducting CH-structure | 1588 |
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| The CH-structure is a new multi-cell drift tube structure operated in the TE21-mode and is well suited for the acceleration of low and medium beta ion and proton beams. Due to the mechanical stiffness room temperature as well as superconducting CH-cavities can be realised. A 19-cell, beta=0.1 superconducting CH-prototype cavity has been developed and built. First cryogenic tests have been performed at 4.5 K in Frankfurt successfully. An effective accelerating voltage of 3.6 MV has been achieved so far. This corresponds to an electric peak field of 23 MV/m. Actual measurements aim on a localisation of possible field emission centers, afterwards further surface preparation will take place. | ||
| TUPLS053 | Beam Dynamics of a High Current IH-DTL Structure for the TWAC Injector | 1615 |
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| A powerful ion injector based on a laser ion source is needed for an efficient operation of the Tera Watt Accumulator (TWAC) complex including a heavy ion synchrotron and a storage ring, which is under progress now at ITEP, Moscow. The Interdigital H-type drift tube linac (IH-DTL) structure operating at 162 MHz is proposed for the second stage of the injector linac behind of a 81 MHz RFQ. Consisting of independently driven sections with inter-tank quadrupole triplet focusing, this structure will accelerate highly stripped ions with charge-to-mass ratios above 1/3 in the energy range from 1.57 MeV/u at the RFQ exit to 7 MeV/u. Beam currents up to 100 mA are expected for medium ions like Carbon or Aluminum. Since the rf frequency is duplicated at the entrance of the IH-DTL in order to reduce size as well as power consumption, space charge effects are dominant at full current. Beam dynamics and structure parameters are discussed in detail. | ||
| TUPLS082 | The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) | 1690 |
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About 40ns long proton pulses with an energy of 120keV and currents of up to 200mA will be produced at the 150kV high current injector with a rep.rate of up to 250kHz. The main acceleration will be done by a 175MHz-RFQ. After this section the proton bunches will have an energy of about 1.7MeV. A 4-gap cavity will allow for an energy increase up to 2.2MeV.In order to get 1ns short pulses at the Li-7-Target we propose a buncher-system of the Mobley-Type*, whereby periodic deflection at one focus of a dipole-magnet guides the bunche train from the linac on different paths to the other focus, where the n-production traget is located in the time focus.By 7Li(p,n)B·107 reactions low-energy neutron bunches will be produced with an averaged integrated flux-density of 4*107/(cm2 s) at a distance of 0.4m. The upper limit for the neutron spectra will be 500keV. The main challange with respect to this buncher is the strong space charge action, which has to be treated by careful particle simulations. FRANZ is among other duties well suited for (n,gamma)-cross-sectional measurements with astrophysical relevance**/***. It is characterised by high n-intensities and by its pulse-structure.
*Phys. Rev. 88(2), 360-361 (1951). **Phys. Rev. C 71, 025803 (2005).***Phys. Rev. Lett. 94, 092504 (2005). |
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| WEPCH017 | Front-to-end Simulation of the Injector Linac for the Heidelberg Ion Beam Therapy Centre | 1957 |
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| The injector linac of the Heidelberg ion beam therapy centre is currently in the commissioning phase. Its main components are two electron cyclotron resonance ion sources (ECRIS), a radio-frequency quadrupole accelerator (RFQ) and an interdigital H-type drift tube linac (IH-DTL). It will be able to accelerate beams of hydrogen-, helium-, carbon- and oxygen-ions up to a specific energy of 7 MeV per nucleon. This contribution focuses on the beam dynamics simulation of the transport lines and the accelerating structures. Three dedicated tools have been employed: Mirko for the beam transport, RFQmed for the particle dynamics through the RFQ and LORASR for the acceleration in the IH-DTL. Between the different beam dynamics codes interfaces have been implemented and a front-to-end simulation has been performed. Comparisons with alternative programmes confirm the results obtained. The work will enable us to investigate the behaviour of the machine in a theoretical model during the forthcoming operating. | ||
| WEPCH118 | LORASR Code Development | 2194 |
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| LORASR is specialized on the beam dynamics design of Separate Function DTL's based on the 'Combined 0 Degree Structure (KONUS)' beam dynamics concept. The code has been used for the beam dynamics design of several linacs already in operation (GSI-HLI, GSI-HSI, CERN Linac 3, TRIUMF ISAC-I) or scheduled for the near future (Heidelberg Therapy Injector, GSI Proton Linac). Recent code development was focused on the implementation of a new PIC 3D FFT space charge routine, facilitating time-efficient simulations with up to 1 million macro particles routinely, as well as of tools for error study and loss profile investigations. The LORASR code was successfully validated within the European HIPPI Project activities: It is the Poisson solver benchmarking and the GSI UNILAC Alvarez section tracking comparison programme. The error study tools are a stringent necessity for the design of future high intensity linacs. The new LORASR release will have a strong impact on the design of the GSI FAIR Facility Proton Linac, as well as the transmission investigations on the IFMIF Accelerator. This paper presents the status of the LORASR code development and the benchmarking results. | ||
| TUPLS036 | Status of the Linac-commissioning for the Heavy Ion Cancer Therapy Facility HIT | 1571 |
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| A clinical 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. It consists of two ECR ion sources, a 7 MeV/u linac injector and a 6.5 Tm synchrotron to accelerate the ions to final energies of 50-430 MeV/u. The linac comprises a 400 keV/u RFQ and a 7 MeV/u IH-DTL operating at 216.8 MHz. In this contribution the current status of the linear accelerator is reported. After first tests with 1H+ beam of the RFQ at GSI, the commissioning of the accelerator in Heidelberg has already started. The commissioning with beam is performed in three steps for the LEBT, the RFQ and the IH-DTL. For this purpose a versatile beam diagnostic test bench has been designed. It consists of a slit-grid emittance measurement device, transverse pick-ups providing for time of flight energy measurements, SEM-profile grids and different devices for beam current measurements. This paper will provide for a status report of the linac-commissioning. |