Lefevre, T.

Paper	Title	Page
MOOCH02	First Full Beam Loading Operation with the CTF3 Linac	39
	R. Corsini, H.-H. Braun, G. Carron, O. Forstner, G. Geschonke, E. Jensen, L. Rinolfi, D. Schulte, F. Tecker, L. Thorndahl CERN, Geneva M. Bernard, G. Bienvenu, T. Garvey, R. Roux LAL, Orsay A. Ferrari Uppsala University, Uppsala L. Groening GSI, Darmstadt R.F. Koontz, R.H. Miller, R.D. Ruth, A.D. Yeremian SLAC, Menlo Park, California T. Lefevre NU, Evanston
	The aim of the CLIC Study is to investigate the feasibility of a high luminosity, multi-TeV linear e+e- collider. CLIC is based on a two-beam method, in which a high current drive beam is decelerated to produce 30 GHz RF power needed for high-gradient acceleration of the main beam running parallel to it. To demonstrate the outstanding feasibility issues of the scheme a new CLIC Test Facility, CTF3, is being constructed at CERN by an international collaboration. In its final configuration CTF3 will consist of a 150 MeV drive beam linac followed by a 42 m long delay loop and an 84 m combiner ring. The installation will include a 30 GHz high power test stand, a representative CLIC module and a test decelerator. The first part of the linac was installed and commissioned with beam in 2003. The first issue addressed was the generation and acceleration of a high-current drive beam in the "full beam loading" condition where RF power is converted into beam power with an efficiency of more than 90%. The full beam loading operation was successfully demonstrated with the nominal beam current of 3.5 A. A variety of beam measurements have been performed, showing good agreement with expectations.
	Video of talk
	Transparencies
THPLT026	Beam Profile Measurements at PETRA with the Laserwire Compton Scattering Monitor	2526
	T.  Kamps BESSY GmbH, Berlin K. Balewski, H.-C. Lewin, S. Schreiber, K. Wittenburg DESY, Hamburg G.A. Blair, G. Boorman, J. Carter, F. Poirier Royal Holloway, University of London, Surrey S.T. Boogert UCL, London T. Lefevre CERN, Geneva
	The vertical beam profile at the PETRA positron storage ring has been measured using a laserwire scanner. A laserwire monitor is a device which can measure high brilliant beam profiles by scanning a finely focused laser beam non-invasively across the charged particle beam. Evaluation of the Compton scattered photon flux as a function of the laser beam position yields the transverse beam profile. The aim of the experiment at PETRA is to obtain the profile of the positron beam at several GeV energy and several nC bunch charge. Key elements of laserwire systems are currently being studied and are described in this paper such as laser beam optics, a fast scanning system and a photon calorimeter. Results are presented from positron beam profile scans using orbit bumps and a fast scanning scheme.
THPLT147	Beam Halo Monitoring on the CLIC Test Facility 3	2798
	T. Lefevre NU, Evanston H.-H. Braun, E. Bravin, R. Corsini, A.-L. Perrot, D. Schulte CERN, Geneva
	In high intensity accelerators, the knowledge of the beam halo distribution and its generation mechanisms are important issues. In order to study these phenomena, dedicated beam diagnostics must be foreseen. In circular machines, beam halo was monitored by using scrapers and beam loss detectors. In the framework of the CLIC project, beam halo monitoring is currently under development. The proposed device is based on an imaging system and a masking technique, which suppresses the core of the beam to allow direct observation of the beam halo. A first test was performed on the CLIC test facility 3 in 2003. We discuss the performances and the limitations of this technique pointing out our plans for future developments.
THPLT148	Beam Loss Monitoring on the CLIC Test Facility 3	2801
	T. Lefevre, M. Velasco, M. Wood NU, Evanston H.-H. Braun, R. Corsini, M. Gasior CERN, Geneva
	The CLIC test facility 3 (CTF3) provides a 3.5A, 1.5s electron beam pulse of 150MeV at the end of the linac. The average beam power is 4 kW. Beam loss will be monitored all along the linac in order to keep the radiation level as low as possible. The heavy beam loading of the linac can lead to time transients of beam position and size along the pulse. To compensate these transients effectively a beam loss monitor (BLM) technology has to be chosen with a time response faster than a few nanoseconds. In this context, two different tests have been performed in 2003 on the already existing part of the CTF3 accelerator. Several detectors based on different technologies were first tested in parallel to determine which one was the most appropriate. A second test, in which the beam was intentionally lost in well defined conditions, was then made with the aim of comparing the measurements with simulation results. We present here the results of these tests and our conclusion for the new system to be developed.