Author: Gonzalez, O.     [González, O.]
Paper Title Page
WEPPD070 Automatic Tuner Unit Operation for the Microwave System of the ESS-Bilbao H+ Ion Source 2684
  • L. Muguira, I. Arredondo, D. Belver, M. Eguiraun, F.J. Fernandez Huerta, J. Feuchtwanger, N. Garmendia, O. González, P.J. González
    ESS Bilbao, LEIOA, Spain
  • V. Etxebarria, J. Jugo, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  • J. Verdu
    EPFL, Lausanne, Switzerland
  Funding: The present work is supported by the Basque Government and Spanish Ministry of Science and Innovation.
The operation of the waveguide automatic tuner unit (ATU) for optimizing the impedance matching and the RF power coupling in the ESS-Bilbao H+ Ion Source (ISHP) is presented. Since the plasma chamber can be considered as a time varying load impedance for the pulsed RF 2.7 GHz high power generator, several approaches have been studied for accurately measuring the load impedance. In the later case, a set of power detectors connected to electric field probes, IQ demodulators and gain/phase detectors connected to dual directional couplers have been integrated. An experimental comparison of these approaches is presented, showing their accuracy, limitations and error-correction methods. Finally, the control system developed for the automatic operation of the triple capacitive post tuner is described, as well as illustrative results.
WEPPR027 Complete Electromagnetic Design of the ESS-Bilbao RFQ Cold Model 2991
  • A. Vélez, I. Bustinduy, J. Feuchtwanger, N. Garmendia, O. González, I. Madariaga, J.L. Muñoz, D. de Cos
    ESS Bilbao, Bilbao, Spain
  • F.J. Bermejo
    Bilbao, Faculty of Science and Technology, Bilbao, Spain
  • V. Etxebarria, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  In this work, the ESS-Bilbao 352,2 Mhz RFQ Cold Model to be built in the ESS-Bilbao accelerator facility is presented. The Cold Model intends to be a small scale representation of the final 4 meters long RFQ which will be able to accelerate a 75 mA proton beam from 75 keV to 3 MeV. The work shown here covers the complete electromagnetic design process of the Cold Model which will be built in aluminium with a total length of 1 meter. Moreover, in order to find out fabrication tolerances, a longitudinal test modulation in the vane regions similar to the one designed for the final RFQ is included in the Cold Model. This modulation represents also a useful tool in order to test the agreement between measurements and electromagnetic simulations. In addition, a complete parametric study of the RFQ ends and radial matchers is presented as an important design parameter able to adjust the field flatness. Finally, slug tuning rods are also added to be able to test the tuning procedures. A final RFQ Cold Model prototype has been designed and is currently under fabrication.  
THEPPB001 Design and Fabrication of The ESS-Bilbao RFQ Prototype Models 3228
  • I. Bustinduy, F.J. Bermejo, J. Feuchtwanger, N. Garmendia, A. Ghiglino, O. González, P.J. González, I. Madariaga, J.L. Muñoz, I. Rueda, F. Sordo Balbin, A. Vélez, D. de Cos
    ESS Bilbao, Bilbao, Spain
  • V. Etxebarria, J. Portilla
    University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
  • A. Garbayo
    AVS, Eibar, Gipuzkoa, Spain
  • S. Jolly
    UCL, London, United Kingdom
  • S.R. Lawrie, A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  As part of the development of the ESS-Bilbao Accelerator in Spain, two different sets of radio frequency quadrupole (RFQ) models have been developed. On one hand, a set of four oxygen free high conductivity copper weld test models has been designed and manufactured, in order to test different welding methods as well as other mechanical aspects involved in the fabrication of the RFQ. On the other hand, a 352.2 MHz four vane RFQ cold model, with a length of 1 meter, has been designed and built in Aluminum. It serves as a good test bench to investigate the validity of different finite element analysis (FEA) software packages. This is a critical part, since the design of the final RFQ will be based on such simulations. The cold model also includes 16 slug tuners and 8 couplers/pick-up ports, which will allow to use the bead-pull perturbation method, by measuring the electric field profile, Q-value and resonant modes. In order to investigate fabrication tolerances, the cold model also comprises a longitudinal test modulation in the vanes, which is similar to the one designed for the final RFQ.