• A. Palmieri, F. Grespan, A. Pisent
  INFN/LNL, Legnaro (PD)
• F. Scantamburlo
  INFN- Sez. di Padova, Padova

In order to attain the stringent goals that assure the required performances of the IFMIF-EVEDA RFQ in terms of field uniformity, Q-value and RF-induced heat removal capability, the study of the 3D details of the cavity is particularly important. In this paper the main issues regarding the design of the slug tuners, cavity ends and vacuum grids are addressed, as well as the related optimization procedure.

• E. Fagotti, M. Comunian, F. Grespan, A. Palmieri, A. Pisent, C. Roncolato
  INFN/LNL, Legnaro (PD)

The TRASCO RFQ will accelerate the 40 mA cw proton beam from the ion source to the energy of 5 MeV, for the production of intense neutron fluxes for interdisciplinary applications. The RFQ is composed of six modules of 1.2 m each, assembled by means of ultra high vacuum flanges. The structure is made of OFE copper and is fully brazed. RFQ modules were manufactured in CINEL Scientific Instruments S.r.l. while chemical treatments and brazing were done at CERN. This paper covers the brazing results of the last four modules and low power tests performed for preparation to the high power test of the first electromagnetic segment.

• F. Scantamburlo, A. Pepato
  INFN- Sez. di Padova, Padova
• M. Comunian, E. Fagotti, F. Grespan, A. Palmieri, A. Pisent
  INFN/LNL, Legnaro (PD)

In the framework of the IFMIF/EVEDA project, the RFQ is a 9.8 m long cavity, with very challenging mechanicals specifications. In the base line design, the accelerator tank is composed of 18 modules that are flanged together. An RFQ prototype, composed of 2 modules with a reduced length, aimed at testing all the mechanical construction procedure is under construction. In this paper, the thermo-mechanical study by means of 2D thermo structural and 3D fluid-thermal-structural simulations will be described. The measurements made with a cooling water circuit on a part of the RFQ prototype and the comparison with fluid thermal simulation will be reported.

• F. Grespan
  INFN/LNL, Legnaro (PD)
• G. De Michele, S. Ramberger, M. Vretenar
  CERN, Geneva

Post Couplers (PC's) are devices used in order to reduce the effect of perturbations on the operating mode of a DTL, using the resonant coupling stabilization method. In this paper an equivalent circuit for a DTL equipped with PC's is presented, together with a 3D simulation analysis, which can explain the post coupler stabilization principle and define a new tuning strategy for DTL cavities. The PC tuning procedure based on the equivalent circuit and on frequency measurements has been tested and validated with measurements on the Linac4 DTL aluminum model.

• M. Comunian, E. Fagotti, F. Grespan, A. Palmieri, A. Pisent, C. Roncolato
  INFN/LNL, Legnaro (PD)

As far as beam dynamics is concerned, the layout of the PIAVE-ALPI SuperConducting linac, it is injected either by a XTU tandem, up to 14 MV, or by the s-c PIAVE injector, made with 2 SC-RFQ. The linac (at the present 64 cavities for a total voltage up to 48 MV) is build up in two branches connected by an achromatic and isochronous U-bend. The PIAVE-ALPI complex is able to accelerate beams up to A/q = 7. The linac is quite complex due the presence of several accelerating, (SC RFQs and cavities), focusing and transport elements. The linac operation, optimized for the needs of the users, is described. In particular the effects of a flexible use of the cavities on the beam dynamics is addressed. The automatic tuning procedure of the Toutatis-Tracewin programs is used for the simulation, and the comparison with the actual linac performances is reported.