• M. Olvegård, E. Bravin, F. Carra, N.C. Chritin, A.E. Dabrowski, A. Dallocchio, S. Döbert, T. Lefèvre
  CERN, Geneva
• E. Adli
  University of Oslo, Oslo

The CLIC study is based on the so‐called two‐beam acceleration concept and one of the main goals of the CLIC Test Facility 3 is to demonstrate the efficiency of the CLIC RF power production scheme. As part of this facility a Test Beam Line (TBL), presently under commissioning, is a small scale version of a CLIC decelerator. To perform as expected the beam line must show efficient and stable RF power production over 16 consecutive decelerating structures. As the high intensity electron beam is decelerated its energy spread grows by up to 60%. A novel segmented beam dump for time resolved energy measurements has been designed to match the requirements of the TBL. As a complement, a diffusive OTR screen is also installed in the same spectrometer line. The combination of these two devices will provide both a high spatial resolution measurement of both the energy and energy spread and a measurement with a few nanoseconds time response. This paper describes the design of the new segmented dump and presents the results from the first commissioning of the TBL spectrometer line.

• E. Adli
  University of Oslo, Oslo
• A.E. Dabrowski, S. Döbert, M. Olvegård, D. Schulte, I. Syratchev
  CERN, Geneva
• R.L. Lillestol
  NTNU, Trondheim

The CLIC Test Facility 3 Test Beam Line is the first prototype for the CLIC drive beam decelerator. Stable transport of the drive beam under deceleration is a mandatory component in the CLIC two-beam scheme. In the Test Beam Line more than 50% of the total energy will be extracted from a 150 MeV, 28 A electron drive beam, by the use of 16 Power Extraction and Transfer structures. A number of experiments are foreseen to investigate the drive beam characteristics under deceleration in the Test Beam Line, including beam stability, beam blow up and the efficiency of the power extraction. General benchmarking of decelerator simulation and theory studies will also be performed. Specially designed instrumentation including precision BPMs, loss monitors and a time-resolved spectrometer dump will be used for the experiments. This paper describes the experimental program foreseen for the Test Beam Line, including the relevance of the results for the CLIC decelerator studies.