| Paper |
Title |
Page |
| MOPLT075 |
Ideal Waterbag Electron Bunches from an RF Photogun
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725 |
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- O.J. Luiten, M.J. Van der Wiel, S.B. van der Geer
TUE, Eindhoven
- F. Kiewiet
FOM Rijnhuizen, Nieuwegein
- M.J. de Loos
PP, Soest
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With the implementation of fs mode-locked Ti:Sapphire lasers in high-gradient RF photoguns, a new charged particle acceleration regime has emerged, the so-called pancake regime. Pancake bunches have by definition a restframe length which is much smaller than the bunch radius. This geometry allows a relatively simple, but effective analytical description of the space-charge dominated, critical initial part of the acceleration trajectory. In high-gradient RF photoguns the pancake regime can be relevant up to several MeV. The general opinion is that extremely short bunches should be avoided during the initial stages of the acceleration process, because high space charge densities are always detrimental to the final beam quality. We show that this is not necessarily true: shorter bunches may even lead to better beams.
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| WEPLT118 |
Performance of the TU/e 2.6 Cell Rf-photogun in the 'Pancake' Regime
|
2125 |
| |
- S.B. van der Geer, G.J.H. Brussaard, O.J. Luiten, M.J. Van der Wiel
TUE, Eindhoven
- G. Pöplau
Rostock University, Faculty of Engineering, Rostock
- M.J. de Loos
PP, Soest
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The 2.6 cell rf-photogun currently in operation at Eindhoven University of Technology has been designed as a booster for a 2 MeV semi-DC accelerator with a field of 1 GV/m. In this paper we present GPT simulation results of the TU/e gun, operated without its pre-accelerator, in the low-charge short-pulse regime. The main part of the paper describes detailed calculations of bunch lengthening due to path-length differences and space-charge effects, making use of high-precision field-maps and the newly developed 3D mesh-based space-charge model of GPT. It is shown that with the present set-up bunches can be produced that are well suited for injection into a planned experiment for controlled acceleration in a plasma-wakefield accelerator.
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| THPLT048 |
Progress in 3D Space-charge Calculations in the GPT Code
|
2589 |
| |
- G. Pöplau, U. Van Rienen
Rostock University, Faculty of Engineering, Rostock
- M.J. de Loos
PP, Soest
- S.B. van der Geer
TUE, Eindhoven
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The mesh-based 3D space-charge routine in the GPT (General Particle Tracer, Pulsar Physics) code scales linearly with the number of particles in terms of CPU time and allows a million particles to be tracked on a normal PC. The crucial ingredient of the routine is a non-equidistant multi-grid Poisson solver to calculate the electrostatic potential in the rest frame of the bunch. The solver has been optimized for very high and very low aspect ratio bunches present in state-of-the-art high-brightness electron accelerators. In this paper, we explore the efficiency and accuracy of the calculations as function of meshing strategy and boundary conditions.
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