First experimental results from the European Union 2-MW coaxial cavity iter gyrotron prototype

J.-P. Hogge, T.P. Goodman, S. Alberti, F. Albajar, K.A. Avramides, P. Benin, S. Bethuys, W. Bin, T. Bonicelli, A. Bruschi, S. Cirant, E. Droz, O. Dumbrajs, D. Fasel, F. Gandini, G. Gantenbein, S. Illy, S. Jawla, J. Jin, S. KernP. Lavanchy, C. Liévin, B. Marlétaz, P. Marmillod, A. Perez, B. Piosczyk, I. Pagonakis, L. Porte, T. Rzesnickl, U. Siravo, M. Thumm, M.Q. Tran

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The European Union is working toward providing 2-MW, coaxial-cavity, continuous-wave (cw) 170-GHz gyrotrons for ITER. Their design is based on results from an experimental preprototype tube having a pulse length of several milliseconds, in operation at Forschungszentrum Karlsruhe (FZK) for several years now. The first industrial prototype tube was designed for cw operation but, in a first phase, aimed at a pulse length of 1 s at the European Gyrotron Test Facility in Lausanne, Switzerland, as part of a phased testing/development program (1 s, 60 s, cw). The first experimental results of the operation of this prototype gyrotron are reported here. The microwave generation was characterized at very short pulse length (<0.01 s) using a load on loan from FZK, and the highest measured output power was 1.4 MW, at a beam energy significantly lower than the design value (83 kV instead of 90 kV), limited by arcing in the tube. The radio-frequency (rf) beam profile was measured to allow reconstruction of the phase and amplitude profile at the window and to provide the necessary information permitting proper alignment of the compact rf loads prior to pulse extension. Arcs in the tube limited the pulse length extension to a few tens of milliseconds. According to present planning, the tube is going to be opened, inspected, and refurbished, depending on the results of the inspection, to allow testing of an improved version of the mode launcher and replacement of some subassemblies.
Original languageEnglish
Pages (from-to)204 - 212
Number of pages9
JournalFusion Science and Technology
Issue number2
Publication statusPublished - 2009
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering
  • Materials Science(all)
  • Mechanical Engineering

Cite this

Hogge, J-P., Goodman, T. P., Alberti, S., Albajar, F., Avramides, K. A., Benin, P., ... Tran, M. Q. (2009). First experimental results from the European Union 2-MW coaxial cavity iter gyrotron prototype. Fusion Science and Technology, 55(2), 204 - 212.