EPAC 2006 - List of Authors

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Zagorodnov, I.

Paper	Title	Page
MOPCH015	Impact of Undulator Wakefileds and Tapering on European X-ray FEL Performance	83
	I. Zagorodnov, M. Dohlus, T. Limberg DESY, Hamburg
	The European X-ray Free-Electron Laser (XFEL) based on self-amplified spontaneous emission (SASE) requires an electron beam with a few kA peak current and a small-gap undulator system up to 250 m in length. The interaction between the high-current electron bunch and the undulator vacuum chamber affects the FEL performance. In this paper we estimate the induced wakefields in elliptical pipe geometry, taking into account the main geometrical variations of the chamber. To study the expected performance in the presence of the calculated wakefields, we are doing start-to-end simulations with the tracking codes ASTRA, CSRtrack and GENESIS. To compensate the wakefield impact on the FEL performance, an adiabatic change of undulator parameters is considered.
THPCH036	Wakefield Calculations for 3D Collimators	2859
	I. Zagorodnov DESY, Hamburg K.L.F. Bane SLAC, Menlo Park, California
	The wakefield effects of the collimators is of concern for future projects. To relax the wakefield effects a gradual transition from a large to a small aperture is used. The impedance of a smooth round collimator is understood well and a good agreement between measurements, theory and simulations is achieved. However, for rectangular flat collimators there is noticeable difference between theory and experiment. Using recently developed time domain numerical approach, which is able to model curved boundaries and does not suffer from dispersion in longitudinal direction, we calculate the short-range geometric wakefields of 3D collimators. This method together with developed by us recently indirect 3D integration algorithm allows to obtain accurate numerical estimations, which are compared to measurements and to analytical results. The applicability range for the analytical formulas is highlighted.
THPCH037	Wakefields Effects of New ILC Cavity Shapes	2862
	I. Zagorodnov DESY, Hamburg N. Solyak Fermilab, Batavia, Illinois
	The operation of International Linear Collider (ILC) requires high gradients and quality factors in accelerating structure. One way to reach it is to modify the cavity shape to reduce the ratio of peak surface magnetic to accelerating field. Two candidate shapes are suggested recently: the Re-entrant shape and the Low-Loss shape. In this paper we estimate numerically longitudinal and transverse short range wake functions for the new shapes. The obtained analytical expressions are used in beam dynamic simulations for ILC lattice. We show that ILC will tolerate the cavities with the new shape and the smaller iris diameter.
THPCH072	Wakefields in the LCLS Undulator Transitions	2952
	K.L.F. Bane SLAC, Menlo Park, California I. Zagorodnov DESY, Hamburg
	We have studied longitudinal wakefields of very short bunches in non-cylindrically symmetric (3D) vacuum chamber transitions using analytical models and the computer program ECHO. The wake (for pairs of well-separated, non-smooth transitions) invariably is resistive, with its shape proportional to the bunch distribution. For the example of an elliptical collimator in a round beam pipe we have demonstrated that—as in the cylindrically symmetric (2D) case—the wake can be obtained from the static primary field of the beam alone. We have obtained the wakes of the LCLS rectangular-to-round transitions using indirect (numerical) field integration combined with a primary beam field calculation. For the LCLS 1 nC bunch charge configuration we find that the total variation in wake-induced energy change is small (0.03% in the core of the beam, 0.15% in the horns of the distribution) compared to that due to the resistive wall wakes of the undulator beam pipe (0.6%).
MOPLS066	Direct Measurement of Geometric and Resistive Wakefields in Tapered Collimators for the International Linear Collider	697
	N.K. Watson, D. Adey, M.C. Stockton Birmingham University, Birmingham D.A.-K. Angal-Kalinin, C.D. Beard, J.L. Fernandez-Hernando, F. Jackson CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire R. Arnold, R.A. Erickson, C. Hast, T.W. Markiewicz, S. Molloy, M.C. Ross, S. Seletskiy, A. Seryi, Z. Szalata, P. Tenenbaum, M. Woodley, M. Woods SLAC, Menlo Park, California R.J. Barlow, A. Bungau, R.M. Jones, G.Yu. Kourevlev, A. Mercer UMAN, Manchester D.A. Burton, J.D.A. Smith, A. Sopczak, R. Tucker Lancaster University, Lancaster C. Densham, G. Ellwood, R.J.S. Greenhalgh, J. O'Dell CCLRC/RAL, Chilton, Didcot, Oxon Y.K. Kolomensky UCB, Berkeley, California M. Kärkkäinen, W.F.O. Müller, T. Weiland TEMF, Darmstadt N. Shales Microwave Research Group, Lancaster University, Lancaster M. Slater University of Cambridge, Cambridge I. Zagorodnov DESY, Hamburg F. Zimmermann CERN, Geneva
	Precise collimation of the beam halo is required in the ILC to prevent beam losses near the interaction region that could cause unacceptable backgrounds for the physics detector. The necessarily small apertures of the collimators lead to transverse wakefields that may result in beam deflections and increased emittance. A set of collimator wakefield measurements has previously been performed in the ASSET region of the SLAC LINAC. We report on the next phase of this programme, which is carried out at the recently commissioned End Station A test facility at SLAC. Measurements of resistive and geometric wakefields using tapered collimators are compared with model predictions from MAFIA and GdfidL and with analytic calculations.
MOPLS067	Test Beam Studies at SLAC's End Station A, for the International Linear Collider	700
	M. Woods, C. Adolphsen, R. Arnold, G.B. Bowden, G.R. Bower, R.A. Erickson, H. Fieguth, J.C. Frisch, C. Hast, R.H. Iverson, Z. Li, T.W. Markiewicz, D.J. McCormick, S. Molloy, J. Nelson, M.T.F. Pivi, M.C. Ross, S. Seletskiy, A. Seryi, S. Smith, Z. Szalata, P. Tenenbaum SLAC, Menlo Park, California D. Adey, M.C. Stockton, N.K. Watson Birmingham University, Birmingham M. Albrecht, M.H. Hildreth Notre Dame University, Notre Dame, Iowa W.W.M. Allison, V. Blackmore, P. Burrows, G.B. Christian, C.C. Clarke, G. Doucas, A.F. Hartin, B. Ottewell, C. Perry, C. Swinson, G.R. White OXFORDphysics, Oxford, Oxon D.A.-K. Angal-Kalinin, C.D. Beard, J.L. Fernandez-Hernando, F. Jackson, A. Kalinin CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire R.J. Barlow, A. Bungau, G.Yu. Kourevlev, A. Mercer UMAN, Manchester S.T. Boogert Royal Holloway, University of London, Surrey D.A. Burton, J.D.A. Smith, R. Tucker Lancaster University, Lancaster W.E. Chickering, C.T. Hlaing, O.N. Khainovski, Y.K. Kolomensky, T. Orimoto UCB, Berkeley, California C. Densham, R.J.S. Greenhalgh CCLRC/DL, Daresbury, Warrington, Cheshire V. Duginov, S.A. Kostromin, N.A. Morozov JINR, Dubna, Moscow Region G. Ellwood, P.G. Huggard, J. O'Dell CCLRC/RAL, Chilton, Didcot, Oxon F. Gournaris, A. Lyapin, B. Maiheu, S. Malton, D.J. Miller, M.W. Wing UCL, London M.B. Johnston University of Oxford, Clarendon Laboratory, Oxford M.F. Kimmitt University of Essex, Physics Centre, Colchester H.J. Schriber, M. Viti DESY Zeuthen, Zeuthen N. Shales, A. Sopczak Microwave Research Group, Lancaster University, Lancaster N. Sinev, E.T. Torrence University of Oregon, Eugene, Oregon M. Slater, M.T. Thomson, D.R. Ward University of Cambridge, Cambridge Y. Sugimoto KEK, Ibaraki S. Walston LLNL, Livermore, California T. Weiland TEMF, Darmstadt M. Wendt Fermilab, Batavia, Illinois I. Zagorodnov DESY, Hamburg F. Zimmermann CERN, Geneva
	The SLAC Linac can deliver to End Station A a high-energy test beam with similar beam parameters as for the International Linear Collider for bunch charge, bunch length and bunch energy spread. ESA beam tests run parasitically with PEP-II with single damped bunches at 10Hz, beam energy of 28.5 GeV and bunch charge of (1.5-2.0)·1010 electrons. A 5-day commissioning run was performed in January 2006, followed by a 2-week run in April. We describe the beamline configuration and beam setup for these runs, and give an overview of the tests being carried out. These tests include studies of collimator wakefields, prototype energy spectrometers, prototype beam position monitors for the ILC Linac, and characterization of beam-induced electro-magnetic interference along the ESA beamline.