GSI, Darmstadt
ITEP, Moscow
IAP, Frankfurt am Main
During the last year several numerical investigations have been started at GSI in order to improve the performance of the linear accelerator facility. The main activities regard the upgrade of the high current UNILAC accelerator including the severe upgrade of the HSI injector, the HITRAP decelerator and, in the frame of the future FAIR project, the development of the new dedicated proton linac. End to end beam dynamics simulations are a powerful tool concerning the machine design, commissioning and optimization. Particle distributions, generated from beam emittance measurements, are transferred through the whole chain of the accelerating structures and beam transport lines. Detailed calculations of the space charge effects as well as external and measured mapping of the structures electromagnetic fields are used to provide the most reliable results. The paper presents a general overview of all activities including a comparison with experimental results.
IAP, Frankfurt am Main
For the development of high energy and high duty cycle RFQs accurate particle dynamic simulation tools are important for optimizing designs, especially in high current applications. To describe the external fields in RFQs, the Poisson equation has to be solved taking the boundary conditions into account. In PteqHI this is now done by using a finite difference method on a grid. This method will be described and simulation results will be compared to different RFQ particle dynamic codes.
Fermilab, Batavia
Similar to many other linear accelerators, the High Intensity Neutron Source requires an RFQ for initial acceleration and formation of the bunched beam structure. The RFQ design includes two main tasks: a) the beam dynamics design resulting in a vane tip modulation table for machining and b) the resonator electromagnetic design resulting in the final dimensions of the resonator. The focus of this paper is on the second task including simulating high power operation of RFQ. We report complete and detailed RF modeling on the HINS RFQ resonator using simulating codes CST Microwave Studio (MWS) and Ansoft High Frequency Structure Simulator (HFSS). All details of the resonator such as input and output radial matchers, the end cut-backs etc have been precisely determined. In the first time a full size RFQ model with modulated vane tips, the power couplers and all tuners installed has been built, and a complete simulation of RFQ tuning has been performed. Finally some aspects of high power operation of RFQ have been investigated. Comparison of the simulation results with experimental measurements demonstrated excellent agreement.