• S.J. Mathot, P. Bourquin, A. Briswalter, Th. Callamand, J. Carosone, N. Favre, J.-M. Geisser, A.M. Lombardi, V. Maire, M. Malabaila, D. Pugnat, Ph. Richerot, B. Riffaud, C. Rossi, M.A. Timmins, A. Vacca, G. Vandoni, M. Vretenar
  CERN, Geneva

The Linac4 RFQ will ac­cel­er­ate the H^- beam from the ion source to the en­er­gy of 3 MeV. The RFQ is com­posed of three sec­tions of 1 meter each, as­sem­bled by means of ultra high vac­u­um flanges and an ad­justable cen­ter­ing ring. The com­plete 3-m long RFQ will be sup­port­ed iso­stat­i­cal­ly over 3 points like a sim­ple beam in order to min­imise the max­i­mum de­flec­tion. The ridge line, used to feed the RF power into the RFQ, will be sup­port­ed via springs and its po­si­tion ad­just­ed in such way that no strain is in­tro­duced into the RFQ at the mo­ment of its con­nec­tion. The me­chan­i­cal de­sign has been done at CERN where the mod­ules are com­plete­ly man­u­fac­tured, heat treat­ed and brazed also. In that way, all of the pro­cess­es are care­ful­ly con­trolled and the in­flu­ence, no­tably of the heat treat­ments, has been un­der­stood in a bet­ter way. Since 2002 sev­er­al four vanes RFQ mod­ules have been brazed at CERN for the TRASCO and IPHI pro­jects. A two-step braz­ing pro­ce­dure has been test­ed. This tech­nique is ac­tu­al­ly used for the as­sem­bly of the CERN Linac4 RFQ. This paper de­scribes the de­sign, the me­chan­i­cal pro­ce­dures adopt­ed for ma­chin­ing and as­sem­bly and the first re­sults ob­tained.