Schulte, D.

Paper	Title	Page
MOZCH02	Start to End Simulations of Low Emittance Tuning and Stabilization	31
	P. Tenenbaum, A. Seryi, M. Woodley SLAC, Menlo Park, California D. Schulte CERN, Geneva N.J. Walker DESY, Hamburg G.R. White Queen Mary University of London, London
	The principal beam dynamics challenge to the subsystems between the damping ring and the collision point of future linear colliders is expected to be the tuning and stabilization required to preserve the transverse emittance and to collide nanometer-scale beams. Recent efforts have focused on realistically modelling the operation and tuning of this region, dubbed the Low Emittance Transport (LET). We report on the development of simulation codes which permit integrated simulation of this complex region, and on early results of these simulations. Future directions of LET simulation are also revealed.
	Video of talk
	Transparencies
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
MOPLT005	An Improved Collimation System for the LHC	536
	R.W. Assmann, O. Aberle, A. Bertarelli, H.-H. Braun, M. Brugger, L. Bruno, O.S. Brüning, S. Calatroni, E. Chiaveri, B. Dehning, A. Ferrari, B. Goddard, E.B. Holzer, J.-B. Jeanneret, J.M. Jimenez, V. Kain, M. Lamont, M. Mayer, E. Métral, R. Perret, S. Redaelli, T. Risselada, G. Robert-Demolaize, S. Roesler, F. Ruggiero, R. Schmidt, D. Schulte, P. Sievers, V. Vlachoudis, L. Vos, G. Vossenberg, J. Wenninger CERN, Geneva I.L. Ajguirei, I. Baishev, I.L. Kurochkin IHEP Protvino, Protvino, Moscow Region D. Kaltchev TRIUMF, Vancouver H. Tsutsui SHI, Tokyo
	The LHC design parameters extend the maximum stored beam energy 2-3 orders of magnitude beyond present experience. The handling of the high-intensity LHC beams in a super-conducting environment requires a high-robustness collimation system with unprecedented cleaning efficiency. For gap closures down to 2mm no beam instabilities may be induced from the collimator impedance. A difficult trade-off between collimator robustness, cleaning efficiency and collimator impedance is encountered. The conflicting LHC requirements are resolved with a phased approach, relying on low Z collimators for maximum robustness and hybrid metallic collimators for maximum performance. Efficiency is further enhanced with an additional cleaning close to the insertion triplets. The machine layouts have been adapted to the new requirements. The LHC collimation hardware is presently under design and has entered into the prototyping and early testing phase. Plans for collimator tests with beam are presented.
MOPLT039	QCD Explorer Based on LHC and CLIC-1	632
	F. Zimmermann, D. Schulte CERN, Geneva
	Colliding 7-TeV LHC super-bunches with 75-GeV CLIC bunch trains can provide electron-proton collisions at very high centre-of-mass energies, opening up a new window into QCD. At the same time, this QCD explorer would employ several key components required for both an LHC upgrade and CLIC. We here present a possible parameter set of such a machine, study the consequences of the collision for both beams, and estimate the attainable luminosity.
MOPLT108	TESLA Linac-IP Simulations	788
	G.R. White Queen Mary University of London, London D. Schulte CERN, Geneva N.J. Walker DESY, Hamburg
	We have formulated integrated simulations of the transport of the electron and positron bunches in the Linear Collider from the linac entrance through the beam delivery system and the interaction region, taking wakefield effects into account. We have set up the simulations to run on the 64-cpu prototpye Grid cluster at QMUL and generated results for various sets of input parameters for the TESLA and NLC machines. For TESLA we have evaluated the distortion of the phase-space of the bunches at the interaction point due to wakefields. We have calculated the luminosity degradation and the production of photons and e+e- pairs. We have simulated the performance of the intra-train beam feedback systems based on bunch position, angle and luminosity measures, and have evauated the luminosity recovery potential of these systems for TESLA and NLC.
TUPLT013	Calculating LHC Tuning Knobs using Various Methods	1159
	W. Wittmer, D. Schulte, F. Zimmermann CERN, Geneva
	By measuring and adjusting the beta-functions at the IP the luminosity is being optimized. In LEP this was done with the two closest doublet magnets. This approach is not applicable for the LHC due to the asymmetric lattice and common beam pipe through the triplet magnets. To control and change the beta-functions quadrupole groups situated on both sides further away from the IP have to be used where the two beams are already separated. The quadrupoles are excited in specific linear combinations, forming the so-called tuning knobs for the IP beta-functions. We compare the performance of such knobs calculated by different methods: (1) matching in MAD, (2) inversion of the re-sponse matrix and singular value decomposition inversion and conditioning and (3) conditioning the response matrix by multidimensional minimization using Hessian method.
WEPLT008	Simulated Emittance Growth due to Electron Cloud for SPS and LHC	1831
	E. Benedetto, D. Schulte, F. Zimmermann CERN, Geneva G. Rumolo GSI, Darmstadt
	The emittance growth caused by an electron cloud is simulated by the HEADTAIL code. The simulation result depends on the number of beam-cloud "interaction points"(IPs), the phase advance between the IPs, the number of macro-particles used to represent beam and cloud, and on the betatron tune. Simulations include a transverse feedback system and, optionally, a large chromaticity, as employed in actual SPS operation. Simulation results for the SPS are compared with observations, and the emittance growth in the LHC is computed as a function of the average electron density.
WEPLT044	Electron-cloud Build-up Simulations and Experiments at CERN	1930
	F. Zimmermann, G. Arduini, V. Baglin, T. Bohl, B.J. Jenninger, J.M. Jimenez, J.-M. Laurent, F. Ruggiero, D. Schulte CERN, Geneva
	We compare the predications of electron-cloud build-up simulations with measurements at the CERN SPS. Specifically, we compare the electron flux at the wall, electron-energy spectra, heat loads, and the spatial distribution of the electrons for two different bunch spacings, with variable magnetic fields, and for several chamber temperatures and associated surface conditions. The simulations employ a modified, improved version of the ECLOUD code. The main changes are briefly described. We finally present updated simulation results for the heat load in the cold LHC arcs.
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.
THPLT017	Review and Comparison of Simulation Codes Modeling Electron-Cloud Build Up and Instabilities	2499
	F. Zimmermann, E. Benedetto, F. Ruggiero, D. Schulte CERN, Geneva G. Bellodi CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon M. Blaskiewicz, L. Wang BNL, Upton, Long Island, New York Y. Cai, M.T.F. Pivi SLAC, Menlo Park, California V.K. Decyk, W. Mori UCLA, Los Angeles, California M.A. Furman LBNL/AFR, Berkeley, California A.F. Ghalam, T. Katsouleas USC, Los Angeles, California K. Ohmi, S.S. Win KEK, Ibaraki G. Rumolo GSI, Darmstadt
	Several computer codes written at various laboratories are employed for modelling the generation and the consequences of an electron cloud. We review the most popular of these programs, which simulate either the build of an electron cloud or the instabilities it produces, and we compare simulation results for identical, or similar, input parameters obtained from the various codes.