• S. Sanz, J. Calero, J.L. Gutiérrez, I. Moya, I. Podadera Aliseda, I. Rodríguez, L. Sanchez, F. Toral
  CIEMAT, Madrid
• P. Bosland, P. Bredy, G. Disset, N. Grouas, P. Hardy, V.M. Hennion, H. Jenhani, J. Migne, A. Mohamed, F. Orsini, J. Plouin, J. Relland
  CEA, Gif-sur-Yvette
• E.N. Zaplatin
  FZJ, Jülich

The IFMIF-EVEDA accelerator will handle a 9 MeV, 125 mA continuous wave (CW) deuteron beam which aims to validate the technology that will be used in the future IFMIF accelerator. The Linac design is based on superconducting Half Wave Resonators (HWR) operating at 4.4 K. Due to space charge associated to the high intensity beam, a strong superconducting focusing magnet package is necessary between cavities, with nested steerers and a Beam Position Monitor (BPM). First of all, this paper describes the preliminary study to choose between two quadrupoles or one solenoid as focusing device, both using NbTi wire. The solenoid shows more advantages, mainly associated to available space and reliability. Then, electromagnetic and mechanical design of the solenoid and the steerers are reported. Special care is taken in order to fulfil the fringe field limit at the cavity flange. An active shield configuration using an anti-solenoid has been adopted, avoiding remnant magnetization associated to passive shielding materials.

• N. Grouas, P. Bosland, P. Bredy, G. Disset, P. Hardy, V.M. Hennion, H. Jenhani, J. Migne, A. Mohamed, F. Orsini, J. Plouin, J. Relland
  CEA, Gif-sur-Yvette
• B. Branas Lasala, I. Podadera Aliseda, S. Sanz, F. Toral
  CIEMAT, Madrid
• E.N. Zaplatin
  FZJ, Jülich

The IFMIF project aims to build a high intensity material irradiation facility which one of the main components is a high intensity deuteron accelerator. A prototype of this accelerator will be built in Rokkasho in Japan. It includes a cryomodule composed of 8 superconducting cavities (HWR) powered by 200 kW couplers to accelerate the deuteron beam from 5 MeV to 9 MeV. The beam is focused inside the cryomodule by 8 superconducting solenoids. The cryomodule design has to respect some severe beam dynamics requirements, in particular a restricted space for the component interfaces and an accurate alignment to be kept during cooling down. A double cryogenic system has been designed as it is necessary to control the cavity cooling independently from the solenoid one. The cryomodule design should also be compatible with its environment in the Rokkasho building. This paper gives then a general overview of the 1rst cryomodule current design and its interfaces. It defines the concept chosen for the Cryogenic System, explains the method foreseen for the assembly and alignment and describes the integration study in Rokkasho.

• H. Jenhani, P. Bosland, P. Bredy, M. Desmons, G. Devanz, G. Disset, N. Grouas, P. Hardy, V.M. Hennion, J. Migne, A. Mohamed, F. Orsini, J. Plouin, J. Relland
  CEA, Gif-sur-Yvette
• B. Branas Lasala, I. Podadera Aliseda, S. Sanz, F. Toral
  CIEMAT, Madrid
• F.M. Mirapeix, C. Palacios
  TTI, Santander
• E.N. Zaplatin
  FZJ, Jülich

The driver of the International Fusion Material Irradiation Facility (IFMIF) consists of two 125 mA, 40 MeV CW deuteron accelerators. A superconducting option for the 5 to 40 MeV linac based on Half-Wave Resonators (HWR) has been chosen. The first cryomodule houses 8 HWR's supplied by high power RF couplers; each of them should be able to operate at 200 kW in CW. This paper will give an overview of the RF design of the 175 MHz CW power coupler. The detailled mechanical studies and the realization will be performed by the Industry. Global approach of the contract with the Industry and the organization of the intermediate validation tests will be discussed. In a second part, the choices and the last advances concerning the couplers RF power test stand will be described.

• F. Orsini, P. Bosland, P. Bredy, G. Disset, N. Grouas, P. Hardy, V.M. Hennion, H. Jenhani, J. Migne, A. Mohamed, J. Plouin, J. Relland
  CEA, Gif-sur-Yvette
• B. Branas Lasala, I. Podadera Aliseda, S. Sanz, F. Toral
  CIEMAT, Madrid
• E.N. Zaplatin
  FZJ, Jülich

In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV, an accelerator prototype is presently under design for the first phase of the project. A superconducting option has been chosen for the 5 MeV RF Linac, based on a cryomodule composed of 8 low-beta Half-Wave Resonators (HWR), 8 Solenoid Packages and 8 RF couplers. This paper will focus on the HWR sub-system: the RF, thermo-mechanical design, and the realization of the first prototype of HWR will be presented. The resonator tuning frequency is controlled by an innovant Cold Tuning System (CTS), located in the central region of the cavity. The different options for tuning will be discussed and the final thermo-mechanical design will be detailed. First validation test results of the CTS are expected for the conference.

• G. Devanz, D. Braud, P. Carbonnier, J.-P. Charrier, S. Chel, M. Desmons, A. Hamdi, H. Jenhani, D. Roudier, P. Sahuquet
  CEA, Gif-sur-Yvette

Coaxial power couplers capable of handling 1MW peak power have been developped for high intensity superconducting proton linacs. They have been conditioned in travelling wave up to the maximum power available on the Saclay test bench, 1.2 MW forward peak power, up to 10% duty cycle. One coupler has been assembled on a 5-cell medium beta cavity in the class 10 area of the clean room, and installed in our horizontal test cryostat CryHoLab. This paper focusses on the RF operation of the coupler in this cryogenic environment and thermal aspects.