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| MOM1MP03 | Resonance Driving Term Experiments: An Overview | betatron, sextupole, multipole, lattice | 22 | |||||
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The frequency analysis of the betatron motion is a valuable tool for the characterization of the linear and non-linear motion of a particle beam in a storage ring. In recent years, several experiments have shown that resonance driving terms can be successfully measured from the spectral decomposition of the turn-by-turn BPM data. The information on the driving terms can be used to correct unwanted resonances, to localize strong non-linear perturbations and provides a valuable tool for the construction of the non-linear model of the real accelerator. In this paper we introduce briefly the theory, the computational tools and we give a review of the resonance driving terms experiments performed on different circular machines.
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| MOA2IS03 | Towards the Description of Long Term Self Consistent Effects in Space Charge Induced Resonance Trapping | beam-losses, simulation, space-charge, emittance | 65 | |||||
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In recent studies the effect of the space charge induced trapping has been shown relevant for long term storage of bunches. There the mechanism of emittance growth and beam loss have been studied for frozen bunch particle distribution. However, when beam loss or halo density are large enough, this approximation have to be reconsidered. We present here a first study on the effect of self consistency in frozen models as intermediate step towards fully 2.5 and 3D simulations.
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| TUPPP16 | Integration of a Large-Scale Eigenmode Solver into the ANSYS(c) Workflow Environment | free-electron-laser, laser, electron, cyclotron | 122 | |||||
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The numerical computation of eigenfrequencies and eigenmodal fields of large accelerator cavities, based on full-wave, three-dimensional models, has attracted considerable interest in the recent past. In particular, it is of vital interest to know the performance characteristics, such as resonance frequency, quality figures and the modal fields, respectively, of such devices prior to construction; given the fact that the physical fabrication of a cavity is expensive and time-consuming, a device that does not comply with its specifications can not be tolerated; a robust and reliable digital prototyping methodology is therefore essential. Furthermore, modern cavity designs typically exhibit delicate and detailed geometrical features that must be considered for obtaining accurate results. At PSI a three-dimensional finite-element code has been developed to compute eigenvalues and eigenfields of accelerator cavities (*). While this code has been validated versus experimentally measured cavity data, its usage has remained somewhat limited due to missing functionality to connect it to industrial grade modeling software. Such an interface would allow creating advanced CAD geometries, meshing them in ANSYS and eventually exporting and analyzing the design in femaxx. We have therefore developed pre- and postprocessing software which imports meshes generated in ANSYS for a femaxx run. A postprocessing step generates a result file than can be imported into ANSYS and further be analyzed there. Thereby, we have integrated femaXX into the ANSYS workflow such that detailed cavity designs leading to large meshes can be analyzed with femaXX, taking advantage of its capability to address very large eigenvalue problems. Additionally, we have added functionality for parallel visualization to femaxx. We present a practical application of the pre- and postprocessing codes and compare the results against experimental values, where available, and other numerical codes when the model has no
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* P. Arbenz, M. Becka, R. Geus, U. L. Hetmaniuk, and T. Mengotti, |
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| WEPPP04 | The FPP Documentation | site, lattice, linac, beam-transport | 191 | |||||
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FPP is the FORTRAN90 library which overloads Berz’s “DA-package” and Forest’s “Lielib.” Furthermore it is also the library which implements a Taylor Polymorphic type. This library is essential to code PTC, the “Polymorphic Tracking Code.” Knowledge of the tools of FPP permits the computation of perturbative quantities in any code which uses FPP such as PTC/MAD-XP. We present here the available HTML documentation.
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