• E. Adli
  University of Oslo, Oslo
• R. Corsini, S. Döbert, A. Dubrovsky, G. Riddone, D. Schulte, I. Syratchev
  CERN, Geneva
• R.J.M.Y. Ruber, V.G. Ziemann
  Uppsala University, Uppsala
• S. Vilalte
  IN2P3-LAPP, Annecy-le-Vieux

The two-beam acceleration scheme foreseen for CLIC and the associated radio-frequency (RF) components will be tested in the Two-beam Test Stand (TBTS) at CTF3, CERN. Of special interest is the performance of the power extraction structures (PETS) and the acceleration structures as well as the stability of the beams in the respective structures. After the recent completion of the TBTS, the first 12 GHz PETS has been tested with beam. Up to 30MW of RF power was extracted from a 5A electron beam, using so called recirculation of the RF power inside the PETS. The TBTS instrumentation, including inductive beam position monitors, allows precise measurement of beam parameters before and after the PETS as well as RF power and phase. Measurements of transverse kicks, energy loss and RF power with recirculation are discussed and compared with estimations, including first measurements of RF pulse shortening probably due to break down.

• M. Olvegård, A.E. Dabrowski, S. Döbert, T. Lefèvre
  CERN, Geneva
• E. Adli
  University of Oslo, Oslo

The CTF3 provides high current (28A) high frequency (12GHz) electron beams, which are used to generate high power radiofrequency pulses at 12GHz by decelerating the electrons in resonant structures. A Test Beam Line (TBL) is currently being built in order to prove the efficiency and the reliability of the RF power production with the lowest level of particle losses. As the beam propagates along the line, its energy spread grows up to 60%. For instrumentation, this unusual characteristic implies the developments of new and innovative techniques. One of the most important tasks is to measure the beam energy spread with a fast time resolution. The detector must be able to detect the energy transient due to beam loading in the decelerating structures (nanosecond) but should also be capable to measure bunch to bunch fluctuations (12GHz). This paper presents the design of the spectrometer line detectors.