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TUAY02 |
End-to-end beam dynamics for CERN Linac4
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79 |
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- A. M. Lombardi, G. Bellodi, J.-B. Lallement, S. Lanzone, E. Zh. Sargsyan
CERN, Geneva
- M. A. Baylac
LPSC, Grenoble
- R. Duperrier, D. Uriot
CEA, Gif-sur-Yvette
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LINAC 4 is a normal conducting H- linac which aims to intensify the proton flux available for the CERN accelerator complex. This injector is designed to accelerate a 65 mA beam of H- ions up to 160 MeV for injection into the CERN Proton Synchrotron Booster. The acceleration is done in three stages : up to 3 MeV with a Radio Frequency Quadrupole (the IPHI RFQ) operating at at 352 MHz, then continued to 90 MeV with drift-tube structures at 352 MHz (conventional Alvarez and Cell Coupled Drift Tube Linac) and, finally, with a Side Coupled Linac at 700MHz. The accelerator is completed by a chopper line at 3 MeV and a transport and matching line to the PS booster. After the overall layout was determined based on general consideration of beam dynamics and RF, a global optimisation based on end-to-end simulation has refined some design choices. The results and lessons learned from the end-to-end simulations are reported in this paper.
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TUBY03 |
Error study of LINAC 4
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137 |
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- M. A. Baylac, J.-M. De Conto, E. Froidefond
LPSC, Grenoble
- E. Zh. Sargsyan
CERN, Geneva
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LINAC 4 is a normal conducting H- linac which aims to intensify the proton flux available for the CERN accelerator complex. This injector is designed to accelerate a 65 mA beam up to 180 MeV. The linac consists of 4 different types of accelerating structures: the 352 MHz IPHI-RFQ, a 352 MHz 3-tank Drift Tube Linac, a 352 MHz Coupled Cavity Drift Tube Linac, and a 704.4 MHz Side Coupled Linac to boost the beam up to the final energy. As LINAC 4 is also designed as a pre-injector for a high power superconducting linac (3.5 GeV, 4 MW) the requirements on acceptable beam emittance growth, halo formation and particle loss are extremely tight. In order to determine the tolerances on the linac components, we examined the sensitivity of the structure to errors on the accelerating field and on the focusing quadrupoles. Simulations were performed between 3 and 180 MeV with the transport code TRACEWIN to evaluate the emittance growth, energy and phase jitter, halo formation of the transported beam and the amount of lost particles. We will present results on individual sensitivities to a single error, as well as the global impact of simultaneous errors on the beam quality. We will mention a f
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WEBX04 |
Measurement strategy for the CERN Linac4 Chopper-line
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262 |
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- J.-B. Lallement, K. Hanke, H. Hori, A. M. Lombardi, E. Zh. Sargsyan
CERN, Geneva
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Linac4 is a new accelerator under study at CERN. It is designed to accelerate H- ions to 160 MeV of energy, for injection into the existing Proton Synchrotron Booster. The low energy section, comprising an H- ion source, a 352 MHz Radio Frequency Quadrupole and a 3 MeV chopper line will be assembled at CERN in the next years. Linac 4 is also designed as an injector for the SPL, a high power proton driver delivering 5MW at 3.5 GeV. In this case the beam losses must be limited to 1 W/m and therefore the formation of transverse and longitudinal halo at low energy becomes a critical issue which has to be measured and controlled. The chopper-line is composed of 11 quadrupoles, 3 bunchers and the chopper itself. Its beam dynamics will be characterized with specific detectors and diagnostic lines. In particular the transverse and longitudinal halo will be measured by a Beam Shape and Halo Monitor (BSHM) with a sensitivity of 10.000 particles per bunch and a time resolution of 2ns. In this paper we present the simulation work in preparation for the measurement campaign scheduled in 2008.
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