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| MOPEC058 | StrahlSim, a Computer Code for the Simulation of Charge Exchange Beam Loss and Dynamic Vacuum in Heavy Ion Synchrotrons | 594 |
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StrahlSim is a unique code for the simulation of charge exchange driven beam loss and dynamic vacuum effects in heavy ion synchrotrons. Dynamic vacuum effects are one of the most challenging problems for accelerators using intermediate charge state, high intensity heavy ion beams (e.g. AGS Booster, LEIR, SIS18). StrahlSim can be used as a design tool for synchrotrons, e.g. for the estimation of pumping power needed to stabilize the dynamic vacuum. Recently, StrahlSim has been extended to simulate time dependent longitudinal pressure profiles. The new code calculates a self-consistent static pressure distribution along the accelerator and simulates local pressure rises caused by dynamic and systematic beam losses. StrahlSim determines the loss distribution of charge exchanged beam ions and respects the beam energy dependence of the charge exchange cross sections. The beam loss calculated by means of the new time dependent longitudinal pressure profiles has been benchmarked with measured data from the latest SIS18 machine experiments. |
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| MOPEC059 | The Frankfurt Neutron Source FRANZ | 597 |
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An intense 2 MeV, 200 mA proton beam will drive a neutron source by the reaction Li7(p,n)Be7 on solid as well as on liquid lithium targets. Actually, the facility is under construction at the physics faculty new experimental hall in Frankfurt. To study in detail the burning of elements in stars by the s-process, a pulsed beam operation with a bunch compressor at the linac exit will offer several Ampere beam current within 1 ns pulse length and with 250 kHz rep. rate at the n - production target. As the upper limit of generated neutrons and the total n- flux at this source are well defined the sample for neutron capture measurements can be placed after a time of flight path as short as 0.8 m only. This will provide highest accessible pulsed neutron flux rates for neutron energies in the 1 - 500 keV range. The highly space charge dominated bunch forming process as well as the ion source, the rf coupled 175 MHz RFQ/DTL - resonator and the target development will be explained. |
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| MOPD031 | Development And Measurements on a Coupled CH Proton Linac for FAIR | 750 |
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For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six coupled CH-cavities operated at 325 MHz. Each cavity will be powered by a 3 MW klystron. For the second acceleration unit from 11.7 to 24.3 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH-cavities. For this second tank technical and mechanical investigations have been done in 2009 to prepare a complete technical concept for manufacturing. Recently, the construction of the prototype has started. The main components of this second cavity will be ready for measurements in spring 2010. At that time the cavity will be tested with dummy stems (made from aluminum) wich will allow precise frequency and field tuning. This paper reports on the technical development and achievements during the last year. It will outline the main fabrication steps towards that novel type of proton DTL. |
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| MOPD032 | Superconducting CH-Cavity Development | 753 |
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At the Institute for Applied Physics a superconducting CH-Cavity (Crossbar H-Mode) has been developed. It is the first multi-cell drift tube cavity for the low and medium energy range of proton and ion linacs. A 19 cell, β = 0.1 prototype cavity has been fabricated and tested successfully with a voltage of 5.6 MV corresponding to gradients of 7 MV/m. The construction of a new superconducting 325 MHz 7-gap CH-cavity has started. This cavity has an optimized geometry with respect to tuning possibilities, high power RF coupling, minimized end cell lengths and options for surface preparation. Static tuning is carried out by small niobium cylinders on the girders. Dynamic tuning is performed by a slow bellow tuner driven by a step motor and a fast bellow tuner driven by a piezo. Additional thermal and mechanical simulations have been performed. It is planned to test the cavity with a 10 mA, 11.4 AMeV (β = 0.158) beam delivered by the Unilac at GSI. Another cavity (f = 217 MHz, β = 0.059) is currently under development for the cw Heavy Ion Linac at GSI. It is the first of nine sc CH-Cavities planned for this project covering an energy range from 1.4 to 7.3 AMeV. |
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| MOPD037 | Recent Studies on a 3-17MeV DTL for EUROTRANS with Respect to RF Structures and Beam Dynamics | 768 |
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EUROTRANS is a EUROpean Research Programme for the TRANSmutation of High Level Nuclear Waste in an Accelerator-Driven System. Frankfurt University is responsible for the development of the 352MHz injector which mainly consists of a 3MeV RFQ and a 3-17MeV CH-DTL. Based on the beam dynamics design, the CH-cavities were designed with the concern to optimize the RF properties. In the cavity design, the tube-gap configurations were modified, so the beam dynamics has been adjusted to fit the new effective gap voltage profiles accordingly. A comparison of the beam dynamics results before and after the RF optimization is presented. |
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| THPEB004 | Slow Extraction from the Superconducting Synchrotron SIS300 at FAIR: Lattice Optimization and Compensation of Field Errors | 3882 |
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With the ability to accelerate heavy ions up to an energy of 32 GeV/u, the SIS300 superconducting (sc) synchrotron is a central part of the new FAIR facility at GSI-Darmstadt. SIS300 will provide beams with a 20-fold increase in energy and, by means of a stretcher mode or a fast ramped mode (1 T/s), 100-10000 times higher average intensity. The beam from SIS300 will be extracted towards the experiments using resonant slow extraction, thus SIS300 becomes the first superconducting synchrotron worldwide with this feature. Coupling and persistent currents are the main practical limitation for operation of sc magnets at high ramping rates and long slow extraction plateaus. The effect of the persistent currents, which are time dependent and depend as well on the magnet's history, is especially critical for slow extraction at low energies. These effects determine the tolerances on magnetic components. In order to address this issue, detailed simulations of beam dynamics at slow extraction have been performed. In particular, the optimization of the lattice and its optical parameters for a low-loss extraction in the presence of steady and time-dependent field components will be presented. |
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| THPEB005 | Scaled Down Experiments for a Stellarator Type Magnetostatic Storage Ring | 3885 |
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The beam transport experiments in toroidal magnets were first described in EPAC08 within the framework of a proposed low energy ion storage ring at Frankfurt University. The experiments with two room temperature 30 degree toroids are needed to design the accumulator ring with closed magnetic fields up to 6~8T. The test setup aims on building an injection system with two beam lines. The primary beam line for the experiments was installed and successfully commissioned in 2009. A special probe for ion beam detection was installed. This modular technique allows online diagnostics of the ion beam along the beam path. In this paper we present new results on beam transport experiments and discuss transport and transverse beam injection properties of that system. |
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| THPD035 | Matching the Laser Generated p - bunch into a CH-DTL | 4355 |
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The concept of laser acceleration of protons by Target Normal Sheath Acceleration TNSA from thin foils could be used to produce a high intensity proton bunch. This proton bunch could be injected into a linac at energies of ten to several tens MeV. A CH- structure is suggested as the linac structure because of its high gradient. The motivation for such a combination is to deliver single beam bunches with quite small emittance values of extremely high particle number - in the order of 10 billion protons per bunch. Optimum emittance values for linac injection are compared with available, laser generated beam parameters. Options and simulation tools for beam matching by pulsed solenoid and CH- structure using LASIN and LORASR codes are presented. |
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| THPD082 | Beam Accumulation in a Stellarator Type Storage Ring | 4473 |
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The stellarator-type storage ring for multi- Ampere proton and ion beams with energies in the range of 100 AkeV to 1AMeV was designed. The main idea for beam confinement with high transversal momentum acceptance was presented in EPAC06 and EPAC08. Stable beam transport in opposite directions is possible through the same aperture with two crossing points along the structure. Elsewhere the beams are separated by the RxB drift motion in curved sections. The space charge compensation through the trapped or circulated electrons will be discussed. This ring is typically suited for experiments in plasma physics and nuclear astrophysics. Here we present the complete simulations for optimization of ring geometry, a stable beam confinement and developments in beam injection. |