Author: Johansson, A.J.
Paper Title Page
MOPC136 The RF Power Source for the High Beta Elliptical Cavities of the ESS Linac 397
  • K. Rathsman, H. Danared, R. Zeng
    ESS, Lund, Sweden
  • A.J. Johansson
    Lund University, Lund, Sweden
  • C. Lingwood
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • R.J.M.Y. Ruber
    Uppsala University, Uppsala, Sweden
  • C. de Almeida Martins
    IST-UTL, Lisbon, Portugal
  The European Spallation Source is an intergovernmental project building a multidisciplinary research laboratory based upon the world’s most powerful neutron source. The main facility will be built in Lund, Sweden. Construction is expected to start around 2013 and the first neutrons will be produced in 2019. The ESS linac delivers 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The 120 high beta elliptical cavities, which operate at a frequency of 704 MHz and accelerate protons from 600 MeV to 2.5 GeV, account for more than half of the total number of rf cavities in the ESS linac and three quarter of the total beam power needed. Because of the large number of rf power sources and the high power level needed, all the design and development efforts for the rf power source have so far been focused on this part of the accelerator. The design and development status of the rf power source is reported in this paper with emphasis on reliability, maintainability, safety, power efficiency, investment cost and production capacity.  
MOPC161 Challenges for the Low Level RF Design for ESS 460
  • A.J. Johansson
    Lund University, Lund, Sweden
  • R. Zeng
    ESS, Lund, Sweden
  The European Spallation Source (ESS) is a planned neutron source to be built in Lund, Sweden, which is planned to produce the first neutrons in 2019. It will have an average beam power at the target of 5 MW, an average current along the Linac of 50 mA, and a pulse repetition rate and length of 20 Hz and 2 ms, respectively. The Linac will have around 200 LLRF stations employed to control a variety of RF cavities such as RFQ, DTL, spoke and elliptical superconducting cavities. The challenges on LLRF systems are mainly the high demands on energy efficiency on all parts of the facility, an operational goal of 95% availability of the facility and a comparably short time from start of final design to commissioning. Running with long pulses, high current and spoke cavities also brings new challenges on LLRF design. In this paper we will describe the consequences these challenges have on the LLRF system, and the proposed solutions and development projects that have started in order to reach these demands.