• C. Rossi, P. Bourquin, J.-B. Lallement, A.M. Lombardi, S.J. Mathot, M.A. Timmins, G. Vandoni, M. Vretenar
  CERN, Geneva
• S. Cazaux, O. Delferrière, M. Desmons, R.D. Duperrier, A. France, D. Leboeuf, O. Piquet
  CEA, Gif-sur-Yvette

The first stage of acceleration in Linac4, the new 160 MeV CERN H^- injector, is a 352 MHz, 3 m long Radiofrequency Quadrupole (RFQ) Accelerator. The RFQ will capture a 70 mA, 45 keV beam from the rf source and accelerate it to 3 MeV, an energy suitable for chopping and injecting the beam in a conventional Drift Tube Linac. Although the RFQ will be initially operated at low duty cycle (0.1%), its design is compatible with higher duty cycle (10%) as the front-end for a possible high-intensity upgrade of the CERN linac facility. The RFQ will be of the brazed-copper design and will be built and assembled at CERN. Beam dynamics design allows for a compact structure made of a single resonant unit. Field symmetry is ensured by fixed tuners placed along the structure. In this paper we present the rf and mechanical design, the beam dynamics and the sensitivity to fabrication and to rf errors.

• N. Chauvin, O. Delferrière, R.D. Duperrier, R. Gobin, P.A.P. Nghiem, D. Uriot
  CEA, Gif-sur-Yvette

The purpose of the IFMIF-EVEDA (International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities) demonstrator is to accelerate a 125 mA cw deuteron beam up to 9 MeV. Therefore, the project requires that the ion source and the low energy beam transport (LEBT) line deliver a 140 mA cw deuteron beam with an energy of 100 keV and an emittance of 0.25 π .mm.mrad (rms normalized) at the entrance of the RFQ. The deuteron beam is extracted from a 2.45 GHz ECR source based on the SILHI design*. A LEBT with a two solenoids focusing system is foreseen to transport and adapt the beam for the RFQ injection. In order to validate the LEBT design, intensive beam dynamics simulations have been carried out using a parallel implementation of a particle-in-cell 3D code which takes into account the space charge compensation of the beam induced by the ionisation of the residual gas. The simulations results (in particular from the emittance growth point of view) performed under several conditions of gas species or gas pressure in the beam line are presented.

*R. Gobin et al, Rev. Sci. Instrum. 79, 02B303 (2008).

• P.A.P. Nghiem, N. Chauvin, O. Delferrière, R.D. Duperrier, A. Mosnier, D. Uriot
  CEA, Gif-sur-Yvette
• M. Comunian
  INFN/LNL, Legnaro, Padova
• C. Oliver
  CIEMAT, Madrid

One major subsystem of IFMIF (International Fusion Materials Irradiation Facility) is its accelerator facility, consisting of two 175 MHz CW accelerators, each accelerating a deuteron beam of 125 mA to the energy of 40 MeV. This high power beam, 10 MW, induces challenging issues that lead to plan a first phase called EVEDA (Engineering Validation and Engineering Design Activity), where only the portion up to 9 MeV of one accelerator will be constructed and tested. For these accelerators, the Parameter Design phase is about to be completed. This paper presents the status of these studies. Due to the very high beam intensity, particular efforts have been dedicated to minimise the space charge effect that can strongly increase the beam size via the halo, and the losses that can prohibit the requested hand-on maintenance. For that, Beam Dynamics simulations have been performed with 10⁶ macro-particles, and a great vigilance has been granted to the emittance growth and the particles on the beam edge. Several possible solutions are presented, for which advantages and drawbacks to fulfil the specifications are discussed.

• A. Facco, A.I. Balabin, R. Paparella, D. Zenere
  INFN/LNL, Legnaro, Padova
• D. Berkovits, J. Rodnizki
  Soreq NRC, Yavne
• J.-L. Biarrotte, S. Bousson, A. Ponton
  IPN, Orsay
• R.D. Duperrier, D. Uriot
  CEA, Gif-sur-Yvette
• V. Zvyagintsev
  TRIUMF, Vancouver

Funding: We acknowledge the financial support of the European Community under the FP6 "Research Infrastructure Action-Structuring the European Research Area" EURISOL DS Project Contract No. 515768 RIDS.
A 1 GeV, 5 mA cw superconducting proton/H^- linac, with the capability of supplying cw primary beam to up to four targets simultaneously by means of a new beam splitting scheme, is under study in the framework of the EURISOL DS project which aims to produce an engineering-oriented design of a next generation European Radioactive beam facility. The EURISOL driver accelerator would be able to accelerate also a 100 muA 3He beam up to 2 GeV, and a 5 mA deuteron beam up to 200 MeV. The linac characteristics and the status of the beam dynamics studies will be presented.

• G. Bellodi, M. Eshraqi, J.-B. Lallement, S. Lanzone, A.M. Lombardi, E.Zh. Sargsyan
  CERN, Geneva
• R.D. Duperrier, D. Uriot
  CEA, Gif-sur-Yvette

Linac4 is a normal conducting H^- linac to be built at CERN as a new injector to the PS Booster and later on as a front end of a Superconducting Proton Linac (SPL). The layout consists of a H^- rf source, a magnetic LEBT, a RFQ (accelerating the beam from 45 keV to 3 MeV), a chopper line, a conventional Drift Tube Linac (from 3 MeV to 50 MeV), a Coupled Cavity Drift Tube Linac (from 50 MeV to 100 MeV) and a pi-mode structure (PIMS, from 100 to 160 MeV), all operating at a frequency of 352 MHz. End-to-end beam dynamics simulations have been carried out in parallel with the codes PATH and TRACEWIN to optimise the design and performance of the accelerator and at the same time to guarantee a cross-check of the results found. An extensive statistical campaign of longitudinal error studies (static and dynamic) was then launched for validation of the proposed design and to assess the maximum level of RF jitter/inaccuracies (in both phase and amplitude) the system can tolerate before beam quality at injection in the PS Booster - and later in the SPL- is compromised.