Author: Piquet, O.
Paper Title Page
THPWO004 RF Tuning of the LINAC4 RFQ 3761
 
  • O. Piquet, Y. Le Noa, J. Novo
    CEA/DSM/IRFU, France
  • M. Desmons, A. France
    CEA/IRFU, Gif-sur-Yvette, France
  • C. Rossi
    CERN, Geneva, Switzerland
 
  The construction of Linac4, the new 160 MeV CERN H injector, has started with the goal of improving the LHC injection chain with a new higher energy linac. The low energy front end of Linac4 is based on a 352 MHz, 3-m long Radiofrequency Quadrupole (RFQ) which accelerates the 70 mA, 45 keV H beam from the ion source to the energy of 3 MeV. The RFQ, made of three modules, one meter each, is of the four-vane type and it has been designed in collaboration between CERN and CEA. Construction has started in 2009 and all the steps of machining and assembly have been done at CERN. The RFQ is equipped with 35 fixed tuners and one waveguide RF port located in the second module. This paper describes the procedure used to tune the accelerating field and the power coupler of the LINAC4 RFQ in order to achieve the nominal voltage profile within ±1% accuracy.  
 
THPWO082 Commissioning of the Linac4 RFQ at the 3 MeV Test Stand 3951
 
  • C. Rossi, L. Arnaudon, G. Bellodi, J.C. Broere, O. Brunner, A.M. Lombardi, J. Marques Balula, P. Martinez Yanez, J. Noirjean, C. Pasquino, U. Raich, F. Roncarolo, M. Vretenar
    CERN, Geneva, Switzerland
  • M. Desmons, A. France, O. Piquet
    CEA/IRFU, Gif-sur-Yvette, France
 
  Linac4, the future 160MeV H injector to the CERN Proton Synchrotron Booster, is presently under construction at CERN as a first step of the planned upgrade of the LHC injectors. The low energy section of LINAC4, consisting of an ion source, a 352.2 MHz Radio Frequency Quadrupole (RFQ) and a chopper line is being commissioned in a dedicated test stand before installation in its final position in the tunnel. The RFQ is designed to accelerate a 45 keV, 70 mA, H beam to 3 MeV, with an efficiency of 95% while preserving the transverse emittance. The RFQ, a four-vane structure 3 m in length, has been designed in collaboration with CEA/IRFU and it has been built at the CERN workshop. The precise fabrication has allowed to achieve a field flatness of 1%. The completion of the accelerating structure in September 2012 was followed by a complete series of bead-pull measurements and by high-power conditioning to the nominal power of 0.39 MW corresponding to a voltage of 78 kV across the 3 meters. Measurements with beam are foreseen during the first half of 2013. This paper reports the results of the low-power and high power RF commissioning as well as the status of beam measurements.