| Paper |
Title |
Page |
| TUAY02 |
End-to-end beam dynamics for CERN Linac4
|
79 |
| |
- 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
|
|
| |
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.
|
|
| TUAY05 |
Application of the extreme value theory to estimate beam loss in an ion linac, using large scale Monte Carlo simulations
|
107 |
| |
- R. Duperrier, D. Uriot
CEA, Gif-sur-Yvette
|
|
| |
The influence of random perturbations of high intensity accelerator elements on the beam losses is considered. This paper presents the error sensitivity study which has been performed for the SPIRAL2 linac in order to define the tolerances for the construction. The proposed driver aims to accelerate a 5 mA deuteron beam up to 20 A. MeV and a 1 mA ion beam for q/A = 1/3 up to 14.5 A. MeV. It consists in an injector (two ECRs sources + LEBTs with the possibility to inject from several sources + Radio Frequency Quadrupole) followed by a superconducting section based on an array of independently phased cavities where the transverse focalization is performed with warm quadrupoles. The correction scheme and the expected losses are described. The Extreme Value Theory is used to estimate the expected beam losses. The described method couples large scale computations to obtain probability distribution functions. The bootstrap technique is used to provide confidence intervals associated to the beam loss predictions. With such a method, it is possible to measure the risk to loose a few watts in this high power linac (up to 200 kW).
|
|
| WEAX03 |
Space charge neutralization and its dynamic effects
|
187 |
| |
- R. Duperrier, N. Pichoff, D. Uriot
CEA, Gif-sur-Yvette
- A. BenIsmail
LLR, Palaiseau
|
|
| |
High-power accelerators are being studied for several projects including accelerator driven neutron or neutrino sources. The low energy part of these facilities has to be carefully optimized to match the beam requirements of the higher energy parts. In this low energy part, the space charge self force, induced by a high intensity beam, has to be carefully controlled. This nonlinear force can generate a large and irreversible emittance growth of the beam. To reduce the space charge (SC), neutralization of the beam charge can be done by capturing some particles of the ionised residual gas in the vacuum chamber. This space charge compensation (SCC) regime complicates the beam dynamics study. This contribution aims to modelize the beam behavior in such a regime and to give order of magnitude to the linac designer for the neutralization rise time and the induced emittance growth.
|
|