EPAC 2006 - List of Keywords

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

simulation

Paper	Title	Other Keywords	Page
MOPCH006	Beam Adaptation at the Infrared FEL, CLIO	undulator, FEL, electron, quadrupole	56
	J.P. Berthet, F. Glotin, J.-M. Ortega CLIO/ELYSE/LCP, Orsay W. Salah The Hashemite University, Zarka
	The infrared free-electron laser CLIO is tunable from 3 to 150 5m by operating its driver RF linear accelerator between 50 and 12 MeV. This is the largest spectral range ever obtained with a single optical cavity. We have studied the electron beam transverse adaptation in the FEL undulator throughout the spectral and energy range. Each beam dimension is measured by a moving wire whose temperature dependant resistivity is monitored. The results are compared with simulations computed with the TRANSPORT code.

MOPCH008	Considerations for Double Pulse Lasing from the BESSY-FEL	FEL, electron, bunching, laser	62
	K. Goldammer, B.C. Kuske, A. Meseck BESSY GmbH, Berlin
	BESSY proposes a linac-based High-Gain Harmonic-Generation (HGHG) free electron laser (FEL) facility with three independent FEL lines. Two to four HGHG stages downconvert the initial seed wavelength (230nm to 460nm) to the desired radiation range (1.24nm to 51nm). High FEL gain is ensured as the seed radiation interacts only with unperturbed parts of the electron bunch in every HGHG-stage. This so-called fresh-bunch-technique relies on dipole chicanes that delay the electron bunches relative to the radiation. Fresh-bunch chicanes are incorporated prior to each modulator in the BESSY-FEL allowing the bunch to completely travel through all undulators. However, simulations show that bunch parts that have previously lased generate a noticeable radiation power level in the final amplifiers. This motivated simulation studies on the significance and applicability of such inherent additional pulses. It is revealed that the BESSY-FEL provides the opportunity to deliver double pulses at the FEL exit being of high interest to the user community. Temporal seperation and intensity levels can be controlled by carefully optimising the properties of the magnetic chicanes.

MOPCH015	Impact of Undulator Wakefileds and Tapering on European X-ray FEL Performance	undulator, radiation, FEL, SASE	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.

MOPCH018	Macro-Pulse Generation in a Storage-Ring Free-Electron Laser: A Single-Particle Plus FEL Numerical Approach	FEL, electron, storage-ring, ELETTRA	89
	F. Curbis, E. Allaria, G. De Ninno ELETTRA, Basovizza, Trieste
	In a storage-ring free-electron laser (FEL), the onset and growth of intra-cavity power at the fundamental resonant wavelength is naturally accompanied by coherent emission at higher harmonics. Contrary to what happens in single-pass linac-based devices, the electron beam is re-circulated in the storage ring and the microbunching becomes thermalized. As a consequence, a correct theoretical understanding of the process requires a proper modelling of the turn-by-turn evolution of the electron-beam phase space, both inside the undulators (where the FEL interaction takes place) and along the ring. To simulate this process we have coupled an ad hoc modified version of the 3D numerical code Ginger (which models the FEL interaction) together with a linear one-turn map (which propagates the electron beam along the ring). We present our results and draw a comparison with previous simplified approaches. We also present the first benchmarking of experiments carried out with the ELETTRA storage-ring FEL.

MOPCH025	Laser Comb: Simulations of Pre-modulated E- Beams at the Photocathode of a High Brightness RF Photoinjector	laser, gun, electron, cathode	98
	M. Boscolo, M. Ferrario, C. Vaccarezza INFN/LNF, Frascati (Roma) I. Boscolo, F. Castelli, S. Cialdi INFN-Milano, Milano P. Musumeci INFN-Roma, Roma
	A density modulated beam at the photocathode though the proper modulation of the laser beam pulse does not change substantially emittance and energy spread, properties directly related to FEL. It has been found that bunch density modulation is transformed into energy modulation along the propagation through the injector. There are some physical arguments that suggest a possibility to use this modulation for the enhancement of the FEL process, or for the production of plasma wakes. Preliminary beam dynamics studies have been carried on to explore the use of electron beam pre-modulation at the cathode to adjust their longitudinal structure at the end of the beamline. Energy modulation at the end of the beamline could eventually be turned into current modulation through a magnetic compressor with R56<0. The feasibility of this experiment has to be investigated carefully, preliminary studies are discussed here. This paper focuses on simulations that explore the properties of the energy modulation at the end of the beamline correlated to the initial characteristics of the train of electron pulses. M. Biagini et al. “Beam Dynamics Studies for the SPARC Project”, Proc. of PAC03.

MOPCH026	A Biperiodic X-band RF Cavity for SPARC	coupling, controls, SLAC, scattering	101
	L. Ficcadenti, M.E. Esposito, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma D. Alesini, B. Spataro INFN/LNF, Frascati (Roma) A. Bacci INFN-Milano, Milano
	The Frascati photo-injector SPARC (Pulsed Self Amplified Coherent Radiation Source) will be equipped with an X-band RF cavity for linearizing emittance to enhance bunch compression and for reducing bunch longitudinal energy spread. A biperiodic cavity working on the pi/2-mode offers some advantages in comparison to a conventional (periodic) cavity despite the need of accurate machining. A copper prototype made of 17 separated cells has been built following numerical simulation. In this paper we report on preliminary measurements of its RF properties. The main characteristics of the cooling system for the final device are also addressed.

MOPCH028	Status of the SPARX FEL Project	emittance, linac, undulator, brightness	107
	C. Vaccarezza, D. Alesini, M. Bellaveglia, S. Bertolucci, M.E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Migliorati, L. Palumbo, L. Pellegrino, M.A. Preger, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stella, F. Tazzioli, M. Vescovi, C. Vicario INFN/LNF, Frascati (Roma) F. Alessandria, A. Bacci, F. Broggi, C. De Martinis, D. Giove, M. Mauri INFN/LASA, Segrate (MI) L. Catani, E. Chiadroni, A. Cianchi, C. Schaerf INFN-Roma II, Roma S. Cialdi, C. Maroli, V. Petrillo, M. Rome, L. Serafini INFN-Milano, Milano F. Ciocci, G. Dattoli, A. Doria, F. Flora, G.P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, P.L. Ottaviani, G. Parisi, L. Picardi, M. Quattromini, A. Renieri, C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma) P. Emma SLAC, Menlo Park, California L. Ficcadenti, A. Mostacci Rome University La Sapienza, Roma M. Mattioli Università di Roma I La Sapienza, Roma P. Musumeci INFN-Roma, Roma S. Reiche, J.B. Rosenzweig UCLA, Los Angeles, California
	The SPARX project consists in an X-ray-FEL facility jointly supported by MIUR (Research Department of Italian Government), Regione Lazio, CNR, ENEA, INFN and Rome University Tor Vergata. It is the natural extension of the ongoing activities of the SPARC collaboration. The aim is the generation of electron beams characterized by ultra-high peak brightness at the energy of 1 and 2 GeV, for the first and the second phase respectively. The beam is expected to drive a single pass FEL experiment in the range of 13.5-6 nm and 6-1.5 nm, at 1 GeV and 2 GeV respectively, both in SASE and SEEDED FEL configurations. A hybrid scheme of RF and magnetic compression will be adopted, based on the expertise achieved at the SPARC high brightness photoinjector presently under commissioning at Frascati INFN-LNF Laboratories. The use of superconducting and exotic undulator sections will be also exploited. In this paper we report the progress of the collaboration together with start to end simulation results based on a combined scheme of RF compression techniques.

MOPCH031	Progress on the Pi-mode X-band RF Cavity for SPARC	vacuum, emittance, radiation	116
	L. Ficcadenti, M.E. Esposito, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma D. Alesini, B. Spataro INFN/LNF, Frascati (Roma) A. Bacci INFN-Milano, Milano
	The Frascati photo-injector SPARC (Pulsed Self Amplified Coherent Radiation Source) will be equipped with an x-band RF cavity for linearizing emittance to enhance bunch compression and for reducing bunch longitudinal energy spread. The nine cell standing wave cavity prototype made of separated cells has been already built and measured. In this paper we report on characterization of the first brazed prototype. Heat load studies have been performed as well to design the cooling system for the final device. D. Alesini et al. Nucl. Instr. and Meth. A 554 (2005) 1.

MOPCH038	Predicted Parameters of the Second Stage of High Power Novosibirsk FEL	FEL, undulator, electron, ERL	124
	A.V. Kuzmin, O.A. Shevchenko, N. Vinokurov BINP SB RAS, Novosibirsk
	The first stage of Novosibirsk high power terahertz FEL was successfully put into operation in 2003. The measured parameters of the FEL turned out to be in a good agreement with calculations [2]. The second and the third stages of the FEL are under construction now. The beam energy at the second stage will be about 20 MeV and the wavelength will change in the range 40-80 μm. In this paper we present the design parameters for the second stage FEL. The simulations were carried out with the help of 1-D code based on macroparticles. This code was previously used for the first stage simulations. E. A. Antokhin et al. NIM A528 (2004) p.15-18.**A. V. Kuzmin et al. NIM A543 (2005) p.114-117.

MOPCH040	Simulations for the FEL Test Facility at MAX-lab within EUROFEL	FEL, undulator, electron, gun	127
	S. Thorin, M. Brandin, S. Werin MAX-lab, Lund M. Abo-Bakr, J. Bahrdt, K. Goldammer BESSY GmbH, Berlin
	Within the EUROFEL project a High Gain Harmonic Generation Free Electron Laser will be constructed at MAX-lab in collaboration with BESSY. The electron bunches will be created in the existing MAX-lab injector and transported to the inside of the MAX II ring where the FEL undulators will be located. To predict FEL performance and stability, simulations of the photo injector, linac, recirculator, transport and undulator sections as well as start to end simulations have been carried out.

MOPCH041	Design of a New Preinjector for the MAX Recirculator to be Used in EUROFEL	gun, emittance, linac, cathode	130
	S. Werin, M. Brandin, T. Hansen, D. Kumbaro, L. Malmgren, S. Thorin MAX-lab, Lund J. Bahrdt BESSY GmbH, Berlin
	The MAX-lab recirculator injector will be equipped with a new preinjector system. The aim is to reduce the emittance, increase the charge and achieve a proper timing between accelerator and laser systems. All is aimed at the MAX-lab test facility for HG built in collaboration with BESSY in the EUROFEL program. The preinjector system consists of a photo cathode RF-gun with an emittance compensating solenoid. Special issues regard the injection of the new beam into the beam path of the MAX recirculator and the conservation of beam parameters.

MOPCH045	A Source of Coherent Soft X-ray Radiation Based on High-order Harmonic Generation and Free Electron Lasers	laser, FEL, undulator, electron	142
	M. Gullans, J.S. Wurtele UCB, Berkeley, California G. Penn, A. Zholents LBNL, Berkeley, California
	We examine a scheme for a Free Electron Laser (FEL) harmonic amplifier seeded by a ~30-nm wavelength signal produced using a process of High-order Harmonic Generation (HHG). The seed is first amplified in an optical klystron from ~100 kW to ~30 MW using a 1 GeV electron beam and then is used for an energy modulation of electrons in the downstream undulator. Subsequently, a 100-MW level of radiation at shorter wavelengths down to 4 nm is obtained by bunching the energy modulated electrons and passing the bunched beam through an undulator tuned to the desired harmonic of 30 nm. We also compare this scheme to a more familiar harmonic cascade FEL by replacing the HHG with an additional stage of harmonic generation.

MOPCH047	Study of the Electron Beam Dynamics in the FERMI @ ELETTRA Linac	electron, emittance, linac, laser	145
	M. Cornacchia, P. Craievich, S. Di Mitri ELETTRA, Basovizza, Trieste I.V. Pogorelov, J. Qiang, M. Venturini, A. Zholents LBNL, Berkeley, California D. Wang MIT, Middleton, Massachusetts R.L. Warnock SLAC, Menlo Park, California
	A study of the electron beam dynamics in the linac is made within the framework of the design of a free electron laser (FEL) at the Syncrotrone Trieste. A scope of the work includes analysis of two operational scenarios, one with relatively long electron bunches of the order of 1.5 ps and a moderate peak current of 500 A and one with shorter bunches of the order of 0.7 ps and higher peak current of the order of 800 A. In both cases, care has been taken to preserve the slice and projected emittances formed in the photocathode gun injector and to minimize the slice energy spread. The latter goal is accomplished by balancing the onset of the microbunching instability driven by the longitudinal space charge forces and the emission of coherent synchrotron radiation using Landau damping produced by a so-called laser heater. Various analytical techniques and tracking codes have been employed to obtain the reported results. C. Bocchetta, et al., this conference.

MOPCH072	Adjustable Input Coupler Development for Superconducting Accelerating Cavity	cryogenics, ERL, linac, electromagnetic-fields	193
	M.V. Lalayan, M.A. Gusarova, V.I. Kaminsky, A.A. Krasnov, V.A. Makarov, N.P. Sobenin MEPhI, Moscow A.A. Zavadtsev, D.A. Zavadtsev Introscan, Moscow
	The waveguide and coaxial-type input couplers for Energy Recovery Linac type injector cavity electrodynamical and thermal simulation results are presented. The devices are designed to feed the superconducting cavity with up to 500 kW RF power in continuous wave regime at 1.3 GHz operating frequency. The cavity external quality factor adjustment is provided. The heat load to the cryogenic system was lowered to a tolerable level by coupler design optimization.

MOPCH075	Internal Target Effects in the ESR Storage Ring with Cooling	target, electron, ion, storage-ring	202
	V. Gostishchev, K. Beckert, P. Beller, C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck GSI, Darmstadt I.N. Meshkov, A.O. Sidorin, A.V. Smirnov, G.V. Trubnikov JINR, Dubna, Moscow Region
	The accurate description of beam-target effects is important for the prediction of operation conditions in terms of high luminosity and beam quality in the FAIR facility at GSI. Numerical models have been developed to evaluate beam dynamics in ion storage rings, where strong cooling in combination with a dense target is applied. First systematic benchmarking experiments were carried out at the existing ESR storage ring at GSI. The influence of the internal target on the beam parameters is demonstrated. Comparison of experimental results with simple models describing the energy loss of the beam particles in the target as well as with more sophisticated simulations with the BETACOOL code will be given.

MOPCH093	Design of the Double Electrostatic Storage Ring DESIREE	ion, vacuum, cryogenics, storage-ring	252
	P. Löfgren, G. Andler, L. Bagge, M. Blom, H. Danared, A. Källberg, S. Leontein, L. Liljeby, A. Paal, K.-G. Rensfelt, A. Simonsson MSL, Stockholm H. Cederquist, M. Larsson, S. Rosén, H.T. Schmidt, K. Schmidt FYSIKUM, AlbaNova, Stockholm University, Stockholm
	A double electrostatic storage ring named DESIREE is under construction at the Manne Siegbahn Laboratory and Stockholm University. The two rings will have the same circumference, 9.2 m, and a common straight section where merged beam experiments with ions of opposite signs will be performed. The whole structure will be contained in a single vacuum vessel resulting in a very compact design. In addition to its unique double ring structure it will be possible to cool DESIREE down to 10-20K using cryogenerators. This will reduce the internal vibrational and rotational excitations of stored molecules. A cold system will also result in excellent vacuum conditions where longer lifetimes of the stored beams can be expected. While the ion optical calculations have entered a final phase much of the work is now devoted to solve many of the mechanical and cryogenic challenges of DESIREE. In order to test the mechanical and cryogenic properties of for example insulators, vacuum seals, and laser viewports a small test system has been built. The test system is expected to provide valuable information for the final design of DESIREE.

MOPCH105	A New RF Tuning Method for the End Regions of the IPHI 4-vane RFQ	rfq, quadrupole, dipole, proton	285
	O. Delferriere, M. Desmons, A. France CEA, Gif-sur-Yvette R. Ferdinand GANIL, Caen
	The 3-MeV High Intensity Proton Injector (IPHI) RFQ is constituted by the assembly of three 2-m-long segments. The tuning of the end regions of such an accelerator with respect to the quadrupole mode is generally made by machining the thickness of the end plates. The dipole modes are moved away from the accelerator mode frequency by adding dipole rods and adjusting their length. In the case of the last IPHI RFQ segment, the tuning range given by possible plate thickness was not sufficient to adjust the frequency at 352 Mhz without modifying the notch depth, leading to serious engineering problems for the cooling, new thermo-mechanical simulations and drawings. To avoid these difficulties, a new way has been investigated by replacing the end plate thickness adjustment by a "quadrupole rod" length adjustment. These rods are situated between the beam axis and the dipole rods, and the tuning range is largely increased. The paper will describe this method applied to the IPHI RFQ and some experimental results obtained on the cold model.

MOPCH108	Error Study of LINAC 4	linac, quadrupole, emittance, CERN	294
	M.A. Baylac, J.-M. De Conto, E. Froidefond LPSC, Grenoble E.Zh. Sargsyan CERN, Geneva
	Within the framework of the Joint Research Activity HIPPI (High Intensity Pulsed Proton Injector) of the CARE program, the conception study of the LINAC 4 accelerator which aims to intensify the proton flux available for the CERN injection line is pursued. The linac, operating in pulsed mode at 352 MHz, is designed to accelerate a 65 mA beam of H^- ions up to an energy of 160 MeV. The requirements on acceptable beam emittance growth and particle loss are extremely tight. In order to determine the Drift Tube Linac tolerances, we examined the sensitivity of the LINAC 4 DTL to errors on the accelerating field and the focusing quadrupoles. Simulations were performed with the transport code TRACEWIN (CEA-Saclay, France). We will present results on individual sensitivities to a single error as well as the global impact of alignment and RF errors on the beam quality. Similarly, accelerating structures following the DTL in the LINAC4 design (CCDTL, SCL) have been studied.

MOPCH115	Transverse Space Charge Studies for the ISIS Synchrotron	resonance, space-charge, synchrotron, focusing	312
	C.M. Warsop CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·10¹³ protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Following this upgrade, transverse space charge is expected to be one of the main intensity limitations, and is also a key factor for further machine upgrades. A programme of R&D on transverse space charge is now under way, aiming not only to improve the ISIS ring but also to exploit it as an experimental tool for testing theory and codes. This paper summarises work so far, outlining calculations for coherent envelope modes on ISIS, using numerical solutions of the envelope equation to show the expected behaviour near half integer resonance. Progress on work linking these predictions with more realistic beam models in space charge codes, and extending calculations to images, coupling and non linear resonances will be described. Plans and preparations for experiments, along with initial results, will also be presented.

MOPCH116	Electromagnetic Design of a Radio Frequency Quadrupole for the Front End Test Stand at RAL	rfq, quadrupole, dipole, ion	315
	A. Kurup Imperial College of Science and Technology, Department of Physics, London A.P. Letchford CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	The goal of the RAL front end test stand is to demonstrate cleanly chopped bunches of a 60mA H^- ion beam at 3MeV. The acceleration of the H^- ions from 65keV to 3MeV will be done using a radio frequency quadrupole (RFQ) operating at a resonant frequency of 324MHz. The two types of RFQ considered were a 4-vane and a 4-rod. The 4-vane has a higher Q-value but the post-production adjustment is limited. The 4-rod design is easier to manufacture but requires complicated cooling at 324MHz. The results of electromagnetic simulations using CST Microwave Studio are presented for the 4-vane type and 4-rod type RFQ.

MOPCH117	Mechanical Design and RF Measurement on RFQ for Front-end Test Stand at RAL	rfq, factory, vacuum, coupling	318
	P. Savage, Y.A. Cheng Imperial College of Science and Technology, Department of Physics, London A.P. Letchford CCLRC/RAL/ISIS, Chilton, Didcot, Oxon J.K. Pozimski CCLRC/RAL, Chilton, Didcot, Oxon
	This paper will present the mechanical design and preliminary results of a RF measurement system for the cold model of a 324MHz 4-vane RFQ, which is part of the development of a proton driver front end test stand at the Rutherford Appleton Laboratory (RAL) in the UK. The design concepts will be discussed and some issues in manufacturing of the RFQ will be pointed out, and specific modifications will be explained. Furthermore, results of thermal simulations of the RFQ will be presented together with RF simulations of the resonant frequency, the Q-value and the longitudinal field distribution.

MOPCH120	Ground Motion Study and the Related Effects on the J-PARC	ground-motion, site, KEK, beam-losses	327
	S. Takeda, N. Yamamoto, M. Yoshioka KEK, Ibaraki Y. Nakayama JPOWER, Kanagawa-ken
	The power spectrum density, coherence and cross-spectrum density of the ground motion in the J-PARC site are studied to get the guideline of the beam control systems. J-PARC consists of a 600 MeV linac, a 3 GeV Rapid-cycling synchrotron (RCS) and a 50 GeV synchrotron (MR). MR provides a beam current of 15 micro-A with a period of 3 sec to either the nuclear physics experimental area or the neutrino production target. MR is a very high beam power machine, so its optimum beam loss must be kept fewer than 0.01% of an accelerated beam in order to decrease the radiation damage of accelerator components and to get easy accessibilty to them. From the point of view of beam loss, we give some detailed discussion about the relation between the MR operation and the ground motion using the observed data.

MOPCH122	Realistic Beam Loss Estimation from the Nuclear Scattering at the RCS Charge-exchange Foil	scattering, injection, beam-losses, target	333
	P.K. Saha, H. Hotchi, Y. Irie, F. Noda JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken H. Harada Hiroshima University, Higashi-Hiroshima
	We have developed simulation tools for the realistic beam loss estimation at the RCS(rapid cycling synchrotron) of J-PARC(Japan Proton Accelerator Research Complex). The present simulation concerns an accurate estimation of the beam loss caused by the nuclear scattering at the charge-exchange foil during the multi turn injection period. It can also figure out the loss point in the ring, so would become very useful for the maintenance and optimization as well. The simulation code GEANT together with the SAD(Strategic Accelerator Design) have been used for the present purpose. In this paper, detail simulation method including the result will be discussed.

MOPCH124	Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators	LHC, beam-losses, proton, collimation	336
	V. Kain, S. Beavan, Y. Kadi CERN, Geneva
	Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators the entire collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses as well as for losses expected during a normal filling is presented. The operational implications are discussed.

MOPCH132	Coupled Maps for Electron and Ion Clouds	electron, ion, RHIC, proton	354
	U. Iriso CELLS, Bellaterra (Cerdanyola del Vallès) S. Peggs BNL, Upton, Long Island, New York
	Contemporary electron cloud models and simulations reproduce second order phase transitions, in which electron clouds grow smoothly beyond a threshold from "off" to "on". In contrast, some locations in the Relativistic Heavy Ion Collider (RHIC) exhibit first order phase transition behaviour, in which electron cloud related outgassing rates turn "on" or "off" precipitously. This paper presents a global framework with a high level of abstraction in which additional physics can be introduced in order to reproduce first (and second) order phase transitions. It does so by introducing maps that model the bunch-to-bunch evolution of coupled electron and ion clouds. This results in simulations that run several orders of magnitude faster, reproduce first order phase transitions, and show hysteresis effects. Coupled maps also suggest that additional dynamical phases (like period doubling, or chaos) could be observed.

MOPCH133	An Analytic Calculation of the Electron Cloud Linear Map Coefficient	electron, LHC, RHIC, heavy-ion	357
	U. Iriso CELLS, Bellaterra (Cerdanyola del Vallès) S. Peggs BNL, Upton, Long Island, New York
	The evolution of the electron density during multibunch electron cloud formation can often be reproduced using a bunch-to-bunch iterative map formalism. The coefficients that parameterize the map function are readily obtained by fitting to results from compute-intensive electron cloud simulations. This paper derives an analytic expression for the linear map coefficient that governs weak cloud behaviour from first principles. Good agreement is found when analytical results are compared with linear coefficient values obtained from numerical simulations. This analysis is useful in predicting thresholds beyond which electron cloud formation occurs, and thus in determining safety regions in parameter space where an accelerator can be operated without creating electron clouds. The formalism explicitly shows that the multipacting resonance condition is not a sine qua non for electron cloud formation.

MOPCH135	Benchmarking Electron Cloud Data with Computer Simulation Codes	electron, LEFT, RHIC, BNL	363
	U. Iriso CELLS, Bellaterra (Cerdanyola del Vallès) G. Rumolo CERN, Geneva
	Saturated electron flux and time decay of the electron cloud are experimentally inferred using many electron detector datasets at the Relativistic Heavy Ion Collider (RHIC). These results are compared with simulation results using two independent electron cloud computer codes, CSEC and ECLOUD. Simulation results are obtained over a range of different values for 1) the maximum Secondary Electron Yield (SEY), and 2) the electron reflection probability at zero energy. These results are used to validate parameterization models of the SEY as a function of the electron energy.

MOPCH143	Electromechanical Characterization of Piezoelectric Actuators Subjected to a Variable Preloading Force at Cryogenic Temperature	cryogenics, vacuum, target, linac	387
	M. Fouaidy, N. Hammoudi, M.S. Saki, H. Saugnac, L. Simonet IPN, Orsay
	Piezoelectric actuators are actually used in Fast Active Cold Tuning Systems (FACTS) for SRF cavities. The characteristics, performances and lifetime of these actuators depend on the preloading force applied by the cavity and the FACTS to the piezostacks. Experimental data are needed for reliable and optimum operation of piezostacks in superconducting protons or electrons linacs. In the frame of the CARE project supported by EU, we designed and constructed a dedicated apparatus for studying the electromechanical behavior of prototype piezoelectric actuators subjected to variable preloading force at cryogenic temperatures. This device was successfully used for testing piezoelectric actuators prototypes for T in the range 2K-300K. The dielectric properties as well as dynamic properties were measured including the actuator characteristics when used as force sensor. The corresponding data are reported and discussed.

MOPCH145	Tests Results of the Beta 0.07 and Beta 0.12 Quarter Wave Resonators for the SPIRAL2 Superconducting Linac	SPIRAL2, linac	393
	G. Olry, J.-L. Biarrotte, S. Bousson, C. Joly, T. Junquera, J. Lesrel, G. Martinet, D. Moura, H. Saugnac, P. Szott IPN, Orsay P.-E. Bernaudin, P. Bosland, G. Devanz CEA, Gif-sur-Yvette
	New developments and tests have been carried out on low beta (0.07) and high beta (0.12) 88 MHz superconducting Quarter Wave Resonators. These resonators will be installed in the LINAC driver, respectively in the low beta section, composed of cryomodules A (developed at CEA-Saclay) and the high beta section composed of cryomodules B (developed at IPN-Orsay). Both resonators' types will be equipped with the same power coupler (developed at LPSC-Grenoble) and designed for a maximum power of 20 kW. RF tests results of the prototype cavities and power couplers are reported. The fabrication of the two cryomodules prototypes, fully equipped, is in progress in order to be ready for high power RF tests at 4.2 K at the beginning of 2007.

MOPCH153	Peak Field Optimization for the Superconducting CH Structure	linac, impedance, cryogenics, GSI	415
	H. Liebermann, H. Podlech, U. Ratzinger IAP, Frankfurt-am-Main
	The Cross-Bar H-type (CH) cavity is a multi-gap drift tube structure operated in the H-210 mode which has been developed at the IAP Frankfurt and in collaboration with GSI. Based on detailed numerical simulations a 19 cell prototype cavity from massive Nb was realised. For optimization of the magnetic and electric peak fields, detailed numerical simulations with CST MicroWave Studio have been performed. After successful experiments on the superconducting prototype cavity calculations about improved drift tube geometries with respect to field emission took place. Additionally, the stem geometry was further improved by simulations.

MOPCH157	Structural Analysis for a Half-reentrant Superconducting Cavity	TESLA, vacuum, linac, linear-collider	424
	E. Zaplatin FZJ, Jülich T.L. Grimm, W. Hartung, M. J. Johnson, M.S. Meidlinger, J. Popielarski NSCL, East Lansing, Michigan
	A half-reentrant cavity (1300 MHz, beta=1.0) is being developed at Michigan State University for use in a superconducting linear collider and other applications. The electromagnetic performance of a half-reentrant cell shape is similar to that of a fully reentrant cavity, but a multi-cell half-reentrant cavity can be cleaned using traditional techniques. We present the results of structural analyses of the half-reentrant cavity for the mid-cell, single-cell, and multi-cell cases. The analysis includes the static and dynamic response of the cavity. Stiffening options to minimize the resonant RF frequency shift due to pressure and the Lorentz force are explored.

MOPCH158	HIPPI Triple-spoke Cavity Design	electron, gun, vacuum, resonance	427
	E. Zaplatin, M. Pap, R. Tölle FZJ, Jülich
	In the frames of the European project of High Intensity Pulsed Proton Injector (HIPPI) the 352 MHz, beta=0.48 triple-spoke cavity is under development and will be built at the research center FZJ in Juelich. The criteria and results of the cavity RF and structural analyses are presented.

MOPCH163	Analysis of Wakefields in the ILC Crab Cavity	dipole, luminosity, quadrupole, TESLA	442
	G. Burt, A.C. Dexter Microwave Research Group, Lancaster University, Lancaster C.D. Beard, P. Goudket CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire L. Bellantoni Fermilab, Batavia, Illinois R.M. Jones UMAN, Manchester
	The large crossing angle schemes of the ILC need a correction of bunch orientation at the IP in order to recover a luminosity loss of up to 80%. The orientation of bunches can be changed using a transverse deflecting cavity. The location of the crab cavity would be close to the final focus, and small deflections caused by wakefields in the cavities could cause misalignments of the bunches at the IP. Wakefields in the FNAL CKM cavities have been analysed and their effects studied in view of use as the ILC crab cavity. Numerical simulations have been performed to analyse the transverse wakepotentials of up to quadrupole order modes in this cavity and the effect upon bunches passing through this cavity. Trapped modes within the CKM cavity have been investigated. Perturbation tests of normal conducting models of this cavity have been launched to verify these results. The effect of the final focus quadrupole magnets on the deflection given to the bunch have also been calculated and used to calculate luminosity loss due to wakefields.

MOPCH166	Construction, Tuning and Assembly of the Beta=0.12 SC Ladder Resonator at LNL	target, EURISOL, linac, TTF	451
	G. Bisoffi, E. Bissiato, A. Palmieri INFN/LNL, Legnaro, Padova
	The Ladder resonator is a 4-gap full Nb cavity suitable for the 0.1< beta <0.2 range of high current proton linacs. A beta=0.12 Nb prototype of this cavity has been built by ZANON (Schio, Italy) on the basis of LNL design. In this paper we describe the construction procedure of such cavity, as well as the tuning steps, aimed at the achievement of the target frequency of 352.2 MHz and the desired field uniformity along the four gaps. Related results of RF simulations and room temperature tests are presented. The preparation of the SC test at LNL is at an advanced stage.

MOPCH167	PBG Superconducting Resonant Structures	lattice, pick-up, radiation, cryogenics	454
	M.R. Masullo INFN-Napoli, Napoli A. Andreone, E. Di Gennaro, F. Francomacaro, G. Lamura Naples University Federico II, Napoli V. Palmieri, D. Tonini INFN/LNL, Legnaro, Padova M. Panniello, V.G. Vaccaro Naples University Federico II and INFN, Napoli
	We have realized normal conducting and superconducting “open resonators” based on the Photonic Band Gap (PBG) concept. We present the study, the optimisation and the measurements (from room temperature to 1.5 K) of Copper and Niobium PBG accelerating cavities operating at two different frequencies, 6 GHz and 16 GHz. All the structures are realised by extruding a single bulk piece of material, using a new machining method that minimizes the surface losses caused by the contact between different conducting parts. Measurements on the compact (54 mm external diameter) 16 GHz Nb structure are very good, showing in the superconducting state a quality factor Q =1.2x105 at the lowest temperature (1.5 K), limited by radiation losses only. The shunt impedance measured for the 16 GHz prototype is 70 MOhm/m, underlining the applicability of such resonant structures as accelerating cavities.

MOPCH174	Optimization of the BCP Processing of Elliptical Nb SRF Cavities	LEFT, extraction, insertion, DESY	469
	C. Boffo, C. A. Cooper, A.M. Rowe Fermilab, Batavia, Illinois G. Galasso University of Udine, Udine
	Bulk niobium (Nb) electropolished SRF cavities performing at or above 35 MV/m is an aggressive goal recently put forth by the International Linear Collider (ILC) collaboration. Buffered chemical polishing (BCP) is still the most cost effective and least complex processing technique known today to optimize the surface properties of high gradient single crystal and relatively low gradient polycrystalline SRF cavities. BCP will be the preferred chemical process in the production of the nine-cell third harmonic 3.9 GHz cavities at Fermilab. The internal shape of these cavities will result in uneven material removal rates between iris and equator of the cells. We will describe a thermal-fluid finite element model adopted to simulate the etching process, and thus revealing the issues at hand. Experimental work, such as flow visualization tests performed to verify the simulation, will also be discussed. Finally we are presenting results obtained with a novel device, which allows to homogenize the flow pattern and to resolve the problem.

MOPCH194	Studies of the Alignment Tolerance for the Injector System of the IFUSP Microtron	alignment, microtron, beam-losses, acceleration	517
	T.F. Silva, M.N. Martins, P.B. Rios USP/LAL, Sao Paulo
	The Instituto de Fmsica da Universidade de Sco Paulo (IFUSP) is building a two-stage 38 MeV continuous-wave racetrack microtron. In this work, we describe the determination of alignment tolerances for the injector system of the IFUSP Microtron. This system consists of a linear accelerator with input energy of 100 keV and output energy of 1.8 MeV. The work presented ere involves analysis of our possibilities of alignment, the beam specifications for the acceleration structures and the strength of the correcting coils. Simulations were made using a method based on rotation matrices that allows for misalignments in the optical elements. It uses a tolerance parameter, given by the user, which is interpreted as a standard deviation of the normal misalignment distribution used to shuffle a configuration. A 5% loss of particles is achieved at a tolerance of 0.25-mm, without the inclusion of correcting coils (steerings) in the simulations.

MOPCH195	The LiCAS-RTRS – A Survey System for the ILC	survey, laser, vacuum, CERN	520
	A. Reichold, C. Perry OXFORDphysics, Oxford, Oxon M. Dawson, J. Green, Y. Han, M. Jones, G. Moss, B. Ottewell, R. Wastie JAI, Oxford G. Grzelak Warsaw University, Warsaw D. Kaemtner, J. Prenting, E. Saemann, M. Schloesser DESY, Hamburg
	The ILC requires an unprecedented accuracy and speed for the survey and alignment of its components. The Rapid Tunnel Reference Surveyor (RTRS) is a self-propelled train intended to automatically survey a reference network in the ILC tunnels with a design accuracy of 200 microns over distances of 600 m. A prototype RTRS has been built by the LiCAS collaboration. It will shortly commence operation at DESY. The operation principle of the RTRS will be explained. The status of the project's hardware, software and calibrations as well as the principles and performance of the underlying measurement techniques will be described.

MOPLS001	Large Scale Beam-beam Simulations for the CERN LHC using Distributed Computing	LHC, CERN, dynamic-aperture, beam-beam-effects	526
	W. Herr, E. McIntosh, F. Schmidt CERN, Geneva D. Kaltchev TRIUMF, Vancouver
	We report on a large scale simulation of beam-beam effects for the CERN Large Hadron Collider (LHC). The stability of particles which experience head-on and long-range beam-beam effects was investigated for different optical configurations and machine imperfections. To cover the interesting parameter space required computing resources not available at CERN. The necessary resources were available in the LHC@home project, based on the BOINC platform. At present, this project makes more than 40000 hosts available for distributed computing. We shall discuss our experience using this system during a simulation campaign of more than six months and describe the tools and procedures necessary to ensure consistent results. The results from this extended study are presented and future plans are discussed.

MOPLS003	Tertiary Halo and Tertiary Background in the Low Luminosity Experimental Insertion IR8 of the LHC	background, shielding, LHC, insertion	532
	V. Talanov IHEP Protvino, Protvino, Moscow Region R.W. Assmann, D. Macina, K.M. Potter, S. Redaelli, G. Robert-Demolaize, E. Tsesmelis CERN, Geneva
	In our report we present the results for numerical simulation of tertiary halo and tertiary background in the LHC. We study the case of the proton losses in the betatron cleaning insertion IR7 with the subsequent tertiary halo generation in the downstream experimental insertion IR8. We analyze the formation of tertiary background in the experimental area of the IR8 and evaluate the performance of the machine-detector interface shielding with respect to this source of the background. The results obtained are compared with the previous estimates of the machine-induced background in the low luminosity insertions of the LHC, and the balance between different sources of the background is discussed.

MOPLS004	Estimation and Analysis of the Machine-induced Background at the TOTEM Roman Pot Detectors in the IR5 of the LHC	LHC, background, optics, hadron	535
	V. Talanov IHEP Protvino, Protvino, Moscow Region V. Avati Helsinki University, Department of Physics, University of Helsinki M. Deile, D. Macina CERN, Geneva
	The problem of background generation in the experimental insertion IR5 of the LHC during machine operation in the dedicated TOTEM mode with low intensity beams and the specially designed beta* = 1540 m optics is discussed. The sources of the machine-induced background in the IR5 forward physics areas are identified and their relative importance is evaluated. The results of the background simulation in the IR5 are presented, based on the most recent estimates of the residual gas density for TOTEM beam conditions. The methods for background analysis and rejection are explained.

MOPLS006	Adaptive RF Transient Reduction for High Intensity Beams with Gaps	feedback, LHC, beam-losses, synchrotron	541
	J. Tuckmantel, P. Baudrenghien CERN, Geneva
	When a high-intensity beam with bunch-trains and gaps passes a cavity with a high-gain vector feedback enforcing a constant voltage, large transients appear, stressing the RF high power hardware and increasing the trip rate. By modulating the cavity voltage with a varying periodic waveform (set-function), the RF power can be made constant while still preserving the high feedback gain. The average cavity voltage is conserved but bunches have to settle at slightly shifted positions. A method is derived to obtain this set-function in practice while making no assumptions or measurements of the beam or RF parameters. Adiabatic iterations are made, including the whole machine as an analog computing device, using all parameters as they are. A computer simulation shows the success of the method.

MOPLS007	Monitoring Heavy-ion Beam Losses in the LHC	ion, proton, LHC, collimation	544
	R. Bruce, G. Bellodi, H.-H. Braun, S.S. Gilardoni, J.M. Jowett CERN, Geneva
	The LHC beam loss monitor (BLM) system, primarily designed for proton operation, will survey particle losses and dump the beam if the loss rate exceeds a threshold expected to induce magnet quenches. Simulations of beam losses in the full magnet geometry allow us to compare the response of the BLMs to ion and proton losses and establish preliminary loss thresholds for quenches. Further simulations of beam losses caused by collimation and electromagnetic interactions peculiar to heavy ion collisions determine the positions of extra BLMs needed for ion operation in the LHC.

MOPLS008	Beam Halo on the LHC TCDQ Diluter System and Thermal Load on the Downstream Superconducting Magnets	LHC, collimation, insertion, superconducting-magnet	547
	B. Goddard, R.W. Assmann, A. Presland, S. Redaelli, G. Robert-Demolaize, L. Sarchiapone, Th. Weiler, W.J.M. Weterings CERN, Geneva
	The moveable single-jawed graphite TCDQ diluter must be positioned very close to the circulating LHC beam in order to prevent damage to downstream components in the event of an unsynchronised beam abort. A two-jawed graphite TCS collimator forms part of the TCDQ system. The requirement to place the TCDQ and TCS jaws close to the beam means that the system can intercept a substantial beam halo load. Initial investigations indicated a worryingly high heat load on the Q4 coils. This paper presents the updated load cases, shielding and simulation geometry, and the results of simulations of the energy deposition in the TCDQ system and in the downstream superconducting Q4 magnet. The implications for the operation of the LHC are discussed.

MOPLS010	Measurement of Ion Beam Losses Due to Bound-free Pair Production in RHIC	ion, RHIC, LHC, luminosity	553
	J.M. Jowett, S.S. Gilardoni CERN, Geneva R. Bruce MAX-lab, Lund K.A. Drees, W. Fischer, S. Tepikian BNL, Upton, Long Island, New York S.R. Klein LBNL, Berkeley, California
	When the LHC operates as a Pb⁸²⁺ ion collider, losses of Pb⁸¹⁺ ions, created through Bound-free Pair Production (BFPP) at the collision point, and localized in cold magnets, are expected to be a major luminosity limit. With Au⁷⁹⁺ ions at RHIC, this effect is not a limitation because the Au⁷⁸⁺ production rate is low, and the Au⁷⁸⁺ beam produced is inside the momentum aperture. When RHIC collided Cu²⁹⁺ ions, secondary beam production rates were lower still but the Cu²⁸⁺ ions produced were predicted to be lost at a well-defined location, creating the opportunity for the first direct observation of BFPP effects in an ion collider. We report on measurements of localized beam losses due to BFPP with copper beams in RHIC and comparisons to predictions from tracking and Monte Carlo simulation.

MOPLS018	High-order Effects and Modeling of the Tevatron	COSY, collider, damping, lattice	577
	P. Snopok, M. Berz MSU, East Lansing, Michigan C. Johnstone Fermilab, Batavia, Illinois
	The role and degree of nonlinear contributions to machine performance is a controversial topic in current collider operations and in the design of future colliders. A high-order model has been developed of the Tevatron in COSY, which includes the strongest sources of nonlinearities. Signatures of nonlinear behavior are studied and compared with performance data. The observed nonlinear effects are compared before and after implemention of nonlinear correction schemes.

MOPLS027	Beam-beam Simulations for a Single Pass SuperB-factory	luminosity, emittance, linac, damping	601
	M.E. Biagini INFN/LNF, Frascati (Roma) P. Raimondi, J. Seeman SLAC, Menlo Park, California D. Schulte CERN, Geneva
	A study of beam-beam collisions for an asymmetric single pass SuperB-Factory is presented. In this scheme an electron and a positron beam are first stored and damped in two damping rings, then extracted, compressed and focused to the IP. After collision the two beams are re-injected in the DR to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Very flat beams and round beams were compared in the simulations, with the GuineaPig code, in order to optimize both luminosity performances and beam blow-up after collision. With such approach, luminosities of the order of 10³⁶ /(cm² sec) can be achieved. http://arxiv.org/abs/physics/0512235.**D. Schulte. “Study of electromagnetic and hadronic background in the Interaction Region of the TESLA Collider”, PhD Thesis, Hamburg, 1996.

MOPLS029	Preliminary Study of a Crab Crossing System for DAFNE	luminosity, coupling, betatron, damping	607
	A. Gallo, D. Alesini, F. Marcellini, P. Raimondi, M. Zobov INFN/LNF, Frascati (Roma)
	The implementation of a crab crossing scheme at the Frascati Phi-factory DAFNE is under consideration, together with several other ideas and upgrades to increase the collider luminosity. The crab crossing is beneficial to the luminosity because it is expected to optimize the geometrical superposition of the colliding bunches and to weaken the synchro-betatron beam-beam resonances. The basic specifications of such a system, the expected luminosity increase, a preliminary design of the crab cavities and the architecture of the dedicated RF system are presented.

MOPLS032	Beam-beam Limit and the Degree of Freedom	emittance, damping, luminosity, KEKB	616
	K. Ohmi, K. Oide KEK, Ibaraki E. Perevedentsev BINP SB RAS, Novosibirsk
	Beam-beam limit is caused by chaotic diffusion due to the strong nonlinear force of beam-beam interaction. Degree of freedom in the colliding system is essential for the diffusion. We discuss the diffusion using several models.

MOPLS048	Doubling the PEP-II Luminosity in Simulations	luminosity, damping, emittance, SLAC	649
	Y. Cai, J. Seeman, K.G. Sonnad, U. Wienands SLAC, Menlo Park, California
	The PEP-II luminosity reached 1x10³⁴cm-2s-1 in October 2005. The question of how to increase the luminosity using modest improvements in the PEP-II accelerator in the coming years is the subject of this paper. We found that the parasitic collisions significantly degrade the simulated luminosity as the beam currents are increased from 3A and 1.7A to 4A and 2.2A in the low and high energy rings, respectively. Using the beam-beam code BBI, we systematically optimized the luminosity and showed that a luminosity of over 2x10³⁴cm-2s-1 is achievable within the limits of machine parameters.

MOPLS050	Combined Phase Space Characterization at the PEP-II IP using Single-beam and Luminous-region Measurements	emittance, luminosity, lattice, coupling	655
	A.J. Bevan Queen Mary University of London, London Y. Cai, A.S. Fisher, C. O'Grady, J.M. Thompson, M. Weaver SLAC, Menlo Park, California W. Kozanecki CEA, Gif-sur-Yvette B.F. Viaud Montreal University, Montreal, Quebec
	We present a novel method to characterize the e ± phase space at the IP of the SLAC B-factory, that combines single-beam measurements with a detailed mapping of luminous-region observables. Transverse spot sizes are determined in the two rings with synchrotron-light monitors & extrapolated to the IP using measured lattice functions. The 3-D luminosity distribution, as well as the spatial dependence of the transverse-boost distribution of the colliding beams, are measured using e⁺ e^- –> mu+ mu- events reconstructed in the BaBar tracking detectors; they provide information on the luminous spot size, the e^- angular divergence & the vertical emittance. The specific luminosity, which is proportional to the inverse product of the overlap IP beam sizes, is continuously monitored using Bhabha-scattering events. The combination of these measurements provide constraints on the horizontal & vertical spot sizes, angular divergences, emittances & beta functions of both beams at the IP during routine high-luminosity operation. Preliminary results of this combined-spot size analysis are confronted with measurements of IP beta-functions & overlap IP beam sizes at low beam current.

MOPLS052	Luminosity Improvement at PEP-II Based on Optics Model and Beam-beam Simulation	luminosity, optics, sextupole, synchrotron	661
	Y. Cai, W.S. Colocho, F.-J. Decker, Y. Nosochkov, P. Raimondi, J. Seeman, K.G. Sonnad, M.K. Sullivan, J.L. Turner, M. Weaver, U. Wienands, W. Wittmer, M. Woodley, Y.T. Yan, G. Yocky SLAC, Menlo Park, California
	The model independent analysis (MIA) has been successfully used at PEP-II to understand machine optics and improve the luminosity. However, the rate of success was limited because the improvement of optics does not necessarily lead to increase of luminosity. Recently, we were able to reconstruct MIA model in a full optics code, LEGO, and used it to calculate complete lattice and beam parameters. These parameters were fed to the beam-beam code, BBI, to understand the luminosity histories at PEP-II over the past year. Using these tools, we optimized the luminosity by varying the beam parameters such as emittance. Finally, we implemented an optimized solution with a set of asymmetric horizontal orbit bumps into the machines during a delivery shift with a few percentage gain in luminosity. The solution was retained at PEP-II machines along with the luminosity. Later, these asymmetric bumps also played a vital role in reaching 1x10³⁴cm-2s-1 as the beam currents increased.

MOPLS061	Optimization of the e-e^- Option for the ILC	luminosity, extraction, quadrupole, optics	685
	M. Alabau Pons, M. Alabau Pons, A. Faus-Golfe IFIC, Valencia R. Appleby UMAN, Manchester P. Bambade, O. Dadoun LAL, Orsay
	The e-e^- running mode is one of the interesting physics options for the International Linear Collider. The luminosity for e-e^- collisions is reduced by mutual defocusing due to the strong electromagnetic fields that the bunches experience during collisions. The resulting beamstrahlung energy loss and beam-beam deflection angles as function of the vertical transverse offset are different compared to the e⁺e^- collisions. In this paper, the dependence of these observables with the offset for different beam sizes has been analysed to optimize performances for the e-e^- mode, taking into account the requirements of the beam-beam deflection based intra-train feedback system. A first study of the implications for the final focus and extraction line optics is also presented for the cases of the 2mrad and 20mrad ILC base line crossing angle geometries.

MOPLS065	An ILC Main Linac Simulation Package Based on Merlin	linac, emittance, alignment, klystron	694
	N.J. Walker, D. Kruecker, F. Poirier DESY, Hamburg
	The preservation of the ultra-small vertical emittance in the International Linear Collider (ILC) will require the use of beam-based alignment techniques, the expected performance of which relies heavily on the use of simulation tools. In this report, we present the newest release of a purpose-built ILC main linac simulation tool, based on the Merlin* C++ class library. Examples of results from Dispersion Free Steering (DFS) simulations are also be presented. *http://www.desy.de/~merlin

MOPLS068	Beam Impact of the ILC Collimators	LEFT, electron, monitoring, positron	703
	G. Ellwood, R.J.S. Greenhalgh CCLRC/RAL, Chilton, Didcot, Oxon
	Spoilers in the ILC Beam Delivery System are required to survive a minimum of 1-2 direct impacts from each energetic electron or positron bunch of charged particles without failure, in addition to maintaining low geometric and resistive wall wakefields. The transient shock wave resulting from rapid localised beam heating and its implications for spoiler design are studied using ANSYS. The realistic patterns of energy deposition are taken from FLUKA.The results presented quantify uncertainties in the predictions and consider possible options for spoiler jaws for the ILC.

MOPLS070	Numerical Calculations of Collimator Insertions	impedance, insertion, SLAC, CERN	709
	C.D. Beard CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire J.D.A. Smith Cockcroft Institute, Warrington, Cheshire
	A series of collimator spoilers have been designed and manufactured for testing in the ESA wakefield tests. The purpose of the tests is a benchmarking exercise to assist with the understanding into the causes of wakefields due to spoiler profile and materials. Simulations of the spoiler designs have been used to understand the likely effects that would be observed with the beam tests. Simulations of these collimator insertions have been carried out in MAFIA and GDFIDL, and a comparison of the results completed. The wake potential has been measured, and the corresponding loss factor and kick factors have been calculated. The results from the simulations are discussed in this report.

MOPLS071	TDR Measurements in support of ILC Collimator Studies	impedance, electron, synchrotron, SLAC	712
	C.D. Beard, P.A. Corlett, A.J. Moss, J.H.P. Rogers CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire R.M. Jones Cockcroft Institute, Warrington, Cheshire
	In this report the outcome of the "wire method" cold test, experimental results and their relevance toward the ILC set-up is considered. A wire is stretched through the centre of a vessel along the axis that the electron beam would take, and a voltage pulse representing the electron bunch is passed along the wire. The parasitic mode loss parameter from this voltage can then be measured. The bunch length for the ILC is 0.3mm, requiring a pulse rise time of ~1ps. The fastest rise time available for a time domain reflectrometry (TDR) scope is ~10ps. Reference vessels have been examined to evaluate the suitability of the test gear at comparable bunch structures to the ILC.

MOPLS073	Shower Simulations, Comparison of Fluka, Geant4 and EGS4	radiation, target, SLAC, electron	718
	L. Fernandez-Hernando CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire R.J. Barlow UMAN, Manchester A. Bungau Cockcroft Institute, Warrington, Cheshire L. Keller SLAC, Menlo Park, California N.K. Watson CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	Computer simulations with different packages (Fluka, Geant4 and EGS4) were run in order to determine the energy deposition of an ILC bunch in a spoiler of specified geometry at various depths. The uncertainty in these predictions is estimated by comparison of their results. Various candidate spoiler designs (geometry, material) are studied. These shower simulations can be used as inputs to thermal and mechanical studies using programs such as ANSYS.

MOPLS082	Simulation of the ILC Collimation System Using BDSIM, MARS15 and STRUCT	collimation, extraction, radiation, SLAC	744
	J. Carter, I.V. Agapov, G.A. Blair, L. Deacon Royal Holloway, University of London, Surrey A.I. Drozhdin, N.V. Mokhov Fermilab, Batavia, Illinois Y. Nosochkov, A. Seryi SLAC, Menlo Park, California
	The simulation codes STRUCT, MARS15 and BDSIM are used to simulate in detail the collimation section of the ILC. A comparative study of the collimation system performance is performed, and the key radiation loads are calculated. Results for the latest ILC designs are presented together with their implications for future design iterations.

MOPLS090	Design of a Strip-line Extraction Kicker for CTF3 Combiner Ring	kicker, impedance, CTF3, power-supply	762
	I. Rodriguez, F. Toral CIEMAT, Madrid L. García-Tabarés CEDEX, Madrid A. Ghigo, F. Marcellini INFN/LNF, Frascati (Roma)
	The new CLIC test facility (CTF3) is the latest stage to prove the technical feasibility of the CLIC project. An extraction kicker is necessary for the combiner ring, and it will be a strip-line type device due to lower coupling impedances and straightforward fabrication. The field uniformity together with a correct beam dynamics are the most challenging issues of this design. The main parameters of the kicker are analytically calculated using standard analytic formulae. The numeric modelling and simulation of several possible straight sections are reported, and the characteristic impedance is matched with the 50 Ω load. The field homogeneity, the kick angle and the scattering parameters are calculated in a 3D finite element model. Several manufacturing issues for the first prototype are also outlined.

MOPLS094	Luminosity Tuning at the Interaction Point	sextupole, luminosity, linac, quadrupole	774
	P. Eliasson, M. Korostelev, D. Schulte, R. Tomas, F. Zimmermann CERN, Geneva
	Minimisation of the emittance in a linear collider is not enough to achieve optimal performance. For optimisation of the luminosity, tuning of collision parameters such as angle, offset, waist, etc. is needed, and a fast and reliable tuning signal is required. In this paper tuning knobs are presented, and their optimisation using beamstrahlung as a tuning signal is studied.

MOPLS099	A Study of Failure Modes in the ILC Main Linac	quadrupole, linac, klystron, lattice	789
	D. Schulte, P. Eliasson, A. Latina CERN, Geneva Eckhard. Elsen, D. Kruecker, F. Poirier, N.J. Walker, G.X. Xia DESY, Hamburg
	Failures in the ILC can lead to beam loss or even damage the machine. Also failures that do not lead to beam loss can affect the luminosity performance, in particular since some time is required to recover from them. In the paper a number of different failures is being investigated and the impact on the machine performance is being studied.

MOPLS101	Beam Dynamics and First Operation of the Sub-harmonic Bunching System in the CTF3 Injector	CTF3, CERN, bunching, linac	795
	P. Urschütz, H.-H. Braun, G. Carron, R. Corsini, S. Doebert, T. Lefevre, G. McMonagle, J. Mourier, J.P.H. Sladen, F. Tecker, L. Thorndahl, C.P. Welsch CERN, Geneva
	The CLIC Test Facility CTF3, built at CERN by an international collaboration, aims at demonstrating the feasibility of the CLIC scheme by 2010. The CTF3 drive beam generation scheme relies on the use of a fast phase switch of a sub-harmonic bunching system in order to phase-code the bunches. The amount of charge in unwanted satellite bunches is an important quantity, which must be minimized. Beam dynamics simulations have been used to study the problem, showing the limitation of the present CTF3 design and the gain of potential upgrades. In this paper the results are discussed and compared with beam measurements taken during the first operation of the system.

MOPLS102	Beam Dynamic Studies and Emittance Optimization in the CTF3 Linac at CERN	emittance, CTF3, linac, quadrupole	798
	P. Urschütz, H.-H. Braun, R. Corsini, S. Doebert, F. Tecker CERN, Geneva A. Ferrari UU/ISV, Uppsala
	Small transverse beam emittances and well-known lattice functions are crucial for the 30 GHz power production in the Power Extraction and Transfer Structure (PETS), and for the commissioning of the delay loop of the CLIC Test Facility 3 (CTF3). Following beam-dynamics-simulation results, two additional solenoids were installed in the CTF3 injector in order to improve the emittance. During the runs in 2005 and 2006, an intensive measurement campaign to determine Twiss parameters and beam sizes was launched. The results obtained by means of quadrupole scans for different modes of operation suggest rms emittances well below the nominal (100 pi mm mrad) and a convincing agreement with PARMELA simulations.

MOPLS104	The Progress in Developing Superconducting Third Harmonic Cavity	DESY, coupling, XFEL, TTF	804
	N. Solyak, H. Edwards, M. Foley, I.G. Gonin, E.R. Harms, T.K. Khabiboulline, D.V. Mitchell, D.O. Olis, A.M. Rowe Fermilab, Batavia, Illinois
	XFEL and TTF facilities are planning to use section with a few third harmonic cavities (3.9GHz) upstream of the bunch compressor to improve beam performances [1-2]. Fermilab is developing superconducting third harmonic section for TTFII upgrade. This section will include four cavities equiped with couplers and blade tuners, installed in cryostat. Up to now, two cavities are complete and one of them is under test. The status of the cavity development and preliminary test results are presented in the paper.

MOPLS114	Construction of the Probe Beam Photo-injector of CTF3	emittance, gun, vacuum, laser	828
	J. Brossard, M. Desmons, B.M. Mercier, C.P. Prevost, R. Roux LAL, Orsay
	The paper describes the HF and dynamic beam modelling performed onto the 3 GHz / 2,5 cells photo-injector of the future CTF3 (CLIC Test Facility 3) probe beam linac, whose goal is to demonstrate the feasibility of the 30 GHz accelerating sections in the framework of the CLIC project. The Probe Beam Photo-Injector (PBPI) conception is inspired from the drive beam photo-injector already designed by LAL (Orsay, France) and actually tested in our laboratory. However, the design of PBPI has been simplified with respect to the previous because the charge per bunch is 4 times lower and the number of bunches several orders of magnitude smaller. The internal geometry and the coupling system of the PBPI have been designed with 2D (SUPERFISH) and 3D (HFSS, ANSYS) codes. A detailed analysis of the dissymmetry (induced by the coupling system) of the accelerating field component has been performed. Based on the modified design, PARMELA simulations showed that the technical specifications are fulfilled. The vacuum issue has been also carefully investigated, and NEG (Non Evaporated Getter) technology has been adopted in order to reach the 10^-10 mbar pressure inside the structure.

MOPLS120	Mitigation of Emittance Dilution due to Transverse Mode Coupling in the L-band Linacs of the ILC	emittance, linac, lattice, coupling	843
	R.M. Jones, R.M. Jones UMAN, Manchester R.H. Miller SLAC, Menlo Park, California
	The main L-band linacs of the ILC accelerate 2820 bunches from a center of mass of 10 GeV to 500 GeV (and in the proposed later upgrade, to 1 TeV). The emittance of the vertical plane is approximately 400 times less than that of the horizontal plane. Provided the vertical and horizontal mode dipole frequencies are degenerate, then the motion in each plane is not coupled. However, in reality the degeneracy will more than likely be removed with the eigen modes lying in planes rotated from the x and y planes due to inevitable manufacturing errors introduced in fabricating 20,000 cavities. This gives rise to a transverse coupling in the horizontal-vertical motion and can readily lead to a dilution in the emittance in the vertical plane. We investigate means to ameliorate this emittance dilution by splitting the horizontal-vertical tune of the lattice.

TUZBPA02	Crystal Channelling in Accelerators	extraction, SPS, collimation, proton	945
	V.M. Biryukov IHEP Protvino, Protvino, Moscow Region
	This presentation will begin with a description of the channelling of charged particles through crystals and the use of the channelling effect in accelerators etc. Results from use of crystals for beam deflection and extraction from synchrotrons in Russia, USA and CERN will also be given. Following this the potential advantage of crystals for collimation in high-energy high-intensity machines will be described.
	Transparencies

TUPCH006	A Wideband Intercepting Probe for the TRIUMF Cyclotron	cyclotron, impedance, electron, linac	1001
	V.A. Verzilov, D. Cameron, D.T. Gray, S. Kellogg, M. Minato, W.R. Rawnsley TRIUMF, Vancouver
	An intercepting probe for the TRIUMF cyclotron capable of measuring the phase and time structure of the circulating beam was designed, manufactured, installed into the tank and tested. A model of the probe head in the form of a 50 Ohm parallel plate transmission line was developed and simulated to operate up to 2 GHz. Thermal simulations show that the probe can withstand at least 500 nA of average current for the 500 MeV beam. In laboratory tests the probe demonstrated a bandwidth in excess of 1 GHz. The probe was mounted on a 3 m long drive and is capable of travelling over 0.5 m at an angle of 27 degree w.r.t. the cyclotron radius. The signals extracted from the probe are processed by a pair of diplexers, where low frequency and high frequency components are separated. The low frequency signal is directed to our standard electronics for processing and provides both dc current and a time of flight signal with a rise time of about 100 ns. At the high frequency output a signal-to-noise ratio of about 4 at 250 nA average current and 0.1 % duty cycle was measured in the presence of rf background from the cyclotron resonators. A bunch time structure as short as 1 ns was resolved.

TUPCH007	High Resolution BPM for the Linear Colliders	pick-up, dipole, DESY, collider	1004
	C. Simon, S. Chel, M. Luong, O. Napoly, J. Novo, D. Roudier CEA, Gif-sur-Yvette N. Rouvière IPN, Orsay
	The beam-based alignment and feedback systems which are essential for the operation of the future colliders use some high resolution Beam Position Monitors (BPM). In the framework of CARE/SRF, the task of CEA/DSM/DAPNIA (Saclay) is the design, the fabrication and the beam test of a BPM in collaboration with DESY. This system is composed of a RF re-entrant cavity with a beam pipe radius of 78mm and an analog electronics having several signal processing steps to reject the monopole mode. Thanks to its high position resolution (better than 1μm) and its high time-resolution (around 10ns), it is a candidate for the X-FEL at DESY and the ILC. Indeed the chosen coupling allows the bunch to bunch measurement and the separation between the monopole and dipole modes. Moreover, this BPM is designed to be used in a clean environment, at the cryogenic and room temperatures.

TUPCH013	Numerical Calculations of Position Sensitivity for Linear-cut Beam Position Monitors	pick-up, vacuum, coupling, CERN	1022
	P. Kowina, A.A. Galatis, W. Kaufmann, J. Schoelles GSI, Darmstadt
	In this contribution the results of simulations performed for different geometries of linear-cut Beam Position Monitors (BPMs) are compared for two design types: i)based on metal electrodes and ii)using a metal coated ceramics. The advantage of the ceramic solution is a compact construction allowing easy positioning. Contrary, the construction based on the metal electrodes benefits from its simplicity. The main goals in optimization are the sensitivity and linearity of the position determination. High position sensitivity can be achieved by the reduction of the plate-to-plate cross talks caused by coupling capacities. For instance, the insertion of an additional guard ring into the gap between the active plates leads to an increase of the sensitivity by about 30%. This insertion is necessary in case of ceramic solution: The large ceramics permeability enlarges the coupling capacity by about a factor of four. The careful geometrical arrangement allows to avoid resonances in the interesting frequency range i.e. from 0.2 to 200MHz. The displayed simulations are performed using CST Microwave Studio. The investigated BPMs will be used in the FAIR facility presently under design at GSI.

TUPCH016	Numerical Simulation of Synchrotron Radiation for Bunch Diagnostics	radiation, vacuum, DESY, synchrotron	1031
	A. Paech, W. Ackermann, T. Weiland TEMF, Darmstadt O. Grimm DESY, Hamburg
	For the operation of the VUV-FEL at DESY, Hamburg, the longitudinal charge distribution of the electron bunches that drive the free electron laser is of high importance. One novel method to measure the bunch shape is to analyze the coherent far-infrared synchrotron radiation generated at the last dipole magnet of the first bunch compressor. For the correct interpretation of the results it is mandatory to know how various parameters, like the bunch shape and path, the vacuum chamber walls, the optical beamline, etc., influence the observed spectrum. The aim of this work is to calculate the generation of synchrotron radiation inside the bunch compressor with the emphasis of including the effects of the vertical and horizontal vacuum chamber walls in the vicinity of the last dipole magnet. Challenging problems for the numerical simulations are the very short wavelength and the broad frequency range of interest. As a first step, it is shown how the radiation leaving the vacuum chamber, that is generated by a single point charge, can be calculated with the help of the uniform theory of diffraction (UTD).

TUPCH022	Large Horizontal Aperture BPM for use in Dispersive Sections of Magnetic Chicanes	pick-up, electron, laser, SMA	1043
	K.E. Hacker, H. Schlarb DESY, Hamburg F. Loehl Uni HH, Hamburg
	A beam position monitor with a large horizontal aperture for use in dispersive sections of FLASH magnetic chicanes will be installed in October 2006. It has a horizontal range of 13 cm and a resolution requirement of better than 10 microns. A stripline design mounted perpendicularly to the the electron beam direction is used to provide broadband electrical pulses traveling in opposite directions, the phases of which give a measure of the beam position. The phase measurement will be accomplished through an optical method developed for a beam arrival time monitor. Results from simulation and recent beam arrival-time measurements will be used to justify expectations for the BPM performance.

TUPCH036	Modelling of Diagnostics for Space Charge Studies on the ISIS Synchrotron	space-charge, ion, proton, synchrotron	1082
	B.G. Pine, S.J. Payne, C.M. Warsop CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·10¹³ protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Transverse space charge is a key issue for both present and proposed upgrades to the machine, and is the focus of current R&D studies. Experiments on the ISIS ring are central to this work, therefore understanding and quantifying limitations in present and proposed diagnostics is essential. This paper presents work studying and modelling the ISIS residual gas profile monitors, including the effects of non-uniformity in sweep fields, space charge and images. Progress on related work looking at other important diagnostics, e.g., position and envelope monitoring, will also be summarised.

TUPCH063	Novel Method for Beam Dynamics using an Alpha Particle Source	injection, betatron, closed-orbit, lattice	1157
	A. Sato, M. Aoki, Y. Arimoto, I. Itahashi, Y. Kuno, T. Oki, M. Yoshida Osaka University, Osaka
	PRISM is a future muon source which would provide high intense, monochromatic and pure muon beams. In order to achieve such muon beams we use a technique called Phase Rotation using an FFAG ring (PRISM-FFAG). The PRISM-FFAG ring is now under construction in Osaka university. The Commissioning will start in JFY 2007. In order to investigate the dynamical performances of the FFAG before the actual commissioning, we propose a novel experimental method. The principle of the method and its application to PRISM-FFAG will be described in this paper.

TUPCH064	Beam-based Alignment Strategy for the Group Controlled Magnets System	alignment, quadrupole, proton, controls	1160
	N. Hayashi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken S. Lee, T. Toyama KEK, Ibaraki
	The beam based alignment of the beam position monitor (BPM) becomes an important tool to reduce the closed orbit distortion (COD) in the recent accelerator. Normally, it requires the independent control of the quadrupole field. Changing the current of a quadrupole magnet, one would find the unperturbed position. However, the J-PARC Rapid-Cycling Synchrotron (RCS) has seven quadrupole families and only group of each family can be controlled simultaneously. There is neither separate power supplies nor auxiliary coil windings on each individual magnet. A similar alignment procedure is applicable for the coupled-controlled magnet system, but it becomes very complicated. For the simplest case, three magnets grouped together, four different beam orbits have to be measured at three different BPM locations. The method and some simulation results for J-PARC/RCS case will be presented in this report.

TUPCH072	New Generation Streak Camera Design and Investigation	electron, radiation, space-charge, monitoring	1175
	A.M. Tron LPI, Moscow T.V. Gorlov, I.G. Merinov MEPhI, Moscow
	The only method for electron bunch duration monitoring with a resolution in the order of 10 fs and less is the method of photochronography of the bunch incoherent radiation in the frequency range, for example, of visible light and at realizing streak camera with new principles of its operation. In the paper the streak camera design for measuring both the electron bunches and x-ray pulses duration with the mentioned temporal resolution is presented. The results of the camera investigation, with photoelectron dynamics simulation taking into account space-charge effect and impact of the surface roughness of a spherical photocathode of the 20-50 micrometers radius (forming a modulating gap of spherical configuration) on the camera resolution, are presented and discussed. A. M. Tron and I. G. Merinov. Method of bunch radiation photochronography with 10 femtosecond and less resolution. http://www.physics.ucla.edu/PAHBEB2005/talks/10oct2005/wg2/atron.pdf

TUPCH096	High-intensity Bremsstrahlung Monitoring System for Photonuclear Technologies	electron, photon, radiation, target	1235
	V.L. Uvarov, S.P. Karasyov, V.I. Nikiforov, R.I. Pomatsalyuk, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev, Yu.V. Zhebrovsky NSC/KIPT, Kharkov
	The realization of promising photonuclear technologies (a soft technology for medical isotope production, radioactive waste handling, activation analysis, etc) calls for the sources of high-energy (Egamma>10MeV) and high-intensity (>=10E03W/cm2) photons. These sources may by obtained by converting a beam from a high-current electron Linac into bremsstrahlung. The method of combined activation of a set of foils that have different energy thresholds of the (gamma,n) reactions is proposed to determine the space-energy characteristics of such radiation. In each energy range the geometrical characteristics of the bremsstrahlung flux are reconstructed from the foil surface gamma-activity distribution. The last one is determined through one-dimensional scanning of the foils by a specially designed detecting head that includes a linear matrix of 16 collimated semiconductor detectors (CdZnTe; 2x2x2,mm). A preliminary analysis of the system geometry and applicability of the method was performed by computer simulation based on the PENELOPE software. A developed PC based measuring system with CAMAC interface is described.

TUPCH099	Development of HOM Damped Copper Cavity for the ESRF	impedance, damping, ESRF, LEP	1244
	N. Guillotin, J. Jacob, V. Serriere ESRF, Grenoble
	At the ESRF, HOM driven longitudinal coupled bunch instabilities are currently avoided up to the nominal beam current of 200 mA by precisely controlling the cavity temperatures and thereby the HOM frequencies of the existing five-cell copper cavities. A bunch-by-bunch feedback is presently being commissioned in order to increase the maximum stored current. In parallel, normal conducting strongly HOM damped cavities are under study to possibly replace the five-cell cavities. The design is based on a scaling of the single cell EU cavity: a pillbox geometry with nose cones and three attached ridged waveguides loaded by ferrites for effective HOM damping. We report on the electromagnetic simulation making use of the 3D codes HFSS and GdfidL. They allowed optimizing the shape of both cavity and dampers, including electromagnetic absorbing material with frequency dependent parameters. E. Weihreter et al. A Ridged Circular Waveguide Ferrite Load for Cavity HOM Damping, this conference.

TUPCH101	Modeling of Ultrafast Streak Cameras	electron, cathode, acceleration, electromagnetic-fields	1250
	G. Huang, J.M. Byrd, J. Feng, H.A. Padmore, J. Qiang, W. Wan LBNL, Berkeley, California
	We present progress on modeling of streak camera with application to measurement of ultrafast phenomena. Our approach is based on treating the streak camera as a photocathode gun and applying modeling tools for beam optics, space charge, and electromagnetic fields. We use these models to compare with experimental results from a streak camera developed at the Advanced Light Source. Furthermore, we explore several ideas for achieving sub-100 fsec resolution.

TUPCH108	Characterization of the PEP-II Colliding-beam Phase Space by the Boost Method	emittance, positron, electron, coupling	1262
	M. Weaver SLAC, Menlo Park, California W. Kozanecki CEA, Gif-sur-Yvette B.F. Viaud Montreal University, Montreal, Quebec
	We present a novel approach to characterize the colliding-beam phase space at the interaction point of the energy-asymmetric PEP-II B-Factory. The method exploits the fact that the transverse-boost distribution of e⁺ e^- –> mu+ mu- events reconstructed in the BaBar tracking system, reflects that of the colliding electrons & positrons. The average boost direction, when combined with the measured orientation of the luminous ellipsoid, determines the e⁺e^- crossing angles. Varying the horizontal direction of one beam with respect to the other in a controlled fashion allows to estimate the individual e⁺ and e^- horizontal IP beam sizes. The angular spread of the transverse boost vector provides an accurate measure of the angular spread of the incoming high-energy beam, confirming the presence of a significant beam-beam induced increase of this angular spread. In addition, the longitudinal dependence of the angular spread of the boost vector in the y-z plane allows to extract from the continuously-monitored boost distributions, a weighted average of the vertical IP beta-functions & emittances of the two beams representative of routine high-luminosity operation.

TUPCH111	RF System for the Superconducting Linac Downstream from DEINOS Injector	controls, SOLEIL, linac, ELSA	1271
	P. Balleyguier, J.-L. Lemaire CEA, Bruyères-le-Châtel
	The DEINOS injector will be followed by an accelerator consisting of a LEP-like cryomodule including four 4-cell superconducting cavities. Each of these cavities will be fed by a solid-state amplifier delivering 20 kW in CW operation at 352 MHz. We will use the technology developed by the "Synchrotron SOLEIL" RF team, consisting of merging the power of numerous independent 330 W modules. The design of the low level RF system will be based on our experience with the ELSA accelerator.

TUPCH114	A Ridged Circular Waveguide Ferrite Load for Cavity HOM Damping	vacuum, damping, impedance, radiation	1280
	E. Weihreter, V. Duerr, F. Marhauser BESSY GmbH, Berlin
	A normal conducting HOM damped 500 MHz prototype cavity has been tested with three tapered circular double ridged waveguide to coaxial transitions as HOM couplers, featuring maximum longitudinal and transverse HOM impedances below 5 kOhm and 200 kOhm/m respectively. Numerical simulations indicate that these impedance levels can be further reduced by more than a factor of 3 using homogeneous circular double ridged waveguides for improved coupling to the HOMs. In the present paper the layout of an optimised homogeneous waveguide with "in vacuum" ferrite tiles is presented, including mechanical and thermal design considerations. Low power reflectrometry measurements demonstrate good matching of a prototype load, and high power tests of the ferrite absorber elements indicate that the waveguide load is well suited for the cavity HOM power levels present in state of art 3rd generation SR sources.

TUPCH123	Dipole Stabilizing Rods System for a Four-vane RFQ: Modeling and Measurement on the TRASCO RFQ Aluminum Model at LNL	rfq, dipole, quadrupole, coupling	1301
	F. Grespan, A. Palmieri, A. Pisent INFN/LNL, Legnaro, Padova
	The Dipole Stabilizing Rods (DSR's) are devices used in order to reduce a priori the effect of perturbation on the operating mode of a four-vane RFQ caused by neighboring dipole modes by increasing the frequency spacing between the TE210 mode and dipole modes, without, in principle, affecting the quadrupole TE210 mode. They have proven to be particularly useful in the case of coupled RFQ's whose overall length is significantly greater than the operating wavelength. In this article we present a circuit model of such DSR's, that, used in combination with a transmission line model of a four vane RFQ, has allowed us to predict the dimensioning of the DSR's in the case of the aluminum model of TRASCO RFQ. The DSR parameters and, in general, the accuracy of the model have been also confirmed by HFSS simulations and by RF measurements on the above-mentioned model.

TUPCH126	Outgassing Rate of Highly Pure Copper Electroplating Applied to RF Cavities	vacuum, linac, LEFT, KEK	1307
	T. Abe, T. Kageyama, Y. Saito, H. Sakai, Y. Sato, Y. Takeuchi KEK, Ibaraki Z. Kabeya, T. Kawasumi MHI, Nagoya T. Nakamura, S. Nishihashi, K. Tsujimoto Asahi Kinzoku Co., Ltd., Gifu K. Tajiri Churyo Engineering Co., Ltd., Nagoya
	We plan to apply a new copper electroplating with a high purity and a high electric conductivity to normal-conducting RF cavities for electron or positron storage rings with a high current beam. As reported in 2005 Particle Accelerator Conference, our first test cavity, made of iron, with the electroplated copper surface finished up by electropolishing showed an excellent electric performance compared with the case of cavities made of oxygen free copper. Our next step is to examine the vacuum performance. This paper reports results of the outgassing-rate measurements on our second test cavity together with its fabrication process.

TUPCH127	Fine Grooving of Conductor Surfaces of RF Input Coupler to Suppress Multipactoring	electromagnetic-fields, KEKB, KEK, coupling	1310
	T. Abe, T. Kageyama, H. Sakai, Y. Takeuchi KEK, Ibaraki
	An RF input coupler to feed high power into an accelerating cavity with heavy beam loading undergoes many multipactoring zones due to the wide range of the input RF power. Furthermore, a regular coaxial line is more subject to multipactoring than a rectangular waveguide because of the uniformity of the electromagnetic field. Grooving the conductor surfaces of the coaxial line is a promising method to suppress multipactoring under any conditions expected in the above cases. This paper reports results of our multipactoring simulation study and the high power test of the input coupler with a grooved coaxial line.

TUPCH133	Comparison of Measured and Calculated Coupling between a Waveguide and an RF Cavity Using CST Microwave Studio	coupling, linac, damping, higher-order-mode	1328
	J. Shi, H. Chen, S. Zheng TUB, Beijing D. Li LBNL, Berkeley, California R.A. Rimmer, H. Wang Jefferson Lab, Newport News, Virginia
	Accurate predications of RF coupling between an RF cavity and ports attached to it have been an important study subject for years for RF coupler and higher order modes (HOM) damping design. We report recent progress and a method on the RF coupling simulations between waveguide ports and RF cavities using CST Microwave Studio in time domain (Transit Solver). Comparisons of the measured and calculated couplings are presented. The simulated couplings and frequencies agree within ~ 10% and ~ 0.1% with the measurements, respectively. We have simulated couplings with external Qs ranging from ~ 100 to ~ 100, 000, and confirmed with measurements. The method should also work well for higher Qs, and can be easily applied in RF power coupler designs and HOM damping for normal-conducting and superconducting cavities.

TUPCH137	Design of the RF System for 30 MeV Cyclotron	cyclotron, impedance, vacuum, coupling	1340
	I.S. Jung, D.H. An, J.-S. Chai, H.B. Hong, S.S. Hong, M.G. Hur, H.S. Jang, J. Kang, J.H. Kim, Y.-S. Kim, M.Y. Lee, T.K. Yang KIRAMS, Seoul K.H. Kwon SKKU, Seoul
	LAD (Lab. of Accelerator Development) in KIRAMS (Korea Institute of Radiological & Medical Sciences) developed 13MeV medical cyclotron, named by KIRAMS-13, for PET (Positron Emission Tomography) in 2001. Now, KIRAMS-13 is widespread in Korea through the national project, "Development of Cyclotron and FDG Synthesis module." But, there is just one cyclotron for SPECT(Single Photon Emission Computed Tomography) in Korea, which is made by IBA, Belgium. If some problems are happened, we should shut off the cyclotron until IBA engineer fixes them. So, we decide to develop a 30MeV cyclotron, named KIRAMS-30, which has high-performance compared with existing commercial cyclotrons and will install this machine to radioactive isotopes production and researches in Advanced Radiation Technology Institute. In this paper, we design RF system, such as cavity, power coupler, and so on. At design of RF components, we consider mechanical stability, RF heating and cooling, arcing and multipacting, low maintenance. We simulate KIRAMS-30 with MWS (MicroWave Studio) and present simulation results.

TUPCH141	New Developments for the RF System of the ALBA Storage Ring	storage-ring, synchrotron, insertion, klystron	1346
	F. Pérez, B. B. Baricevic, D. Einfeld, H. Hassanzadegan, A. Salom, P. Sanchez ALBA, Bellaterra
	ALBA is a 3 GeV, 400 mA, 3rd generation Synchrotron Light Source that is in the construction phase in Cerdanyola, Spain. The RF System will have to provide 3.6 MV of accelerating voltage and restore up to 540 kW of power to the electron beam. For that six RF plants, working at 500 MHz, are foreseen. The RF plants will include several new developments: 1) DAMPY cavity: the normal conducting HOM damped cavity developed by BESSY and based in the EU design; six will be installed. 2) CaCo: A cavity combiner to add the power to two 80 kW IOTs to produce the 160 kW needed for each cavity. 3) WATRAX: A waveguide transition to coaxial, specially designed to feed the DAMPY cavities due to the geometrical and cooling constrains. 4) IQ LLRF: The low level RF will be based on the IQ modulation/demodulation technique, both analogue and digital approach are being pursued. This paper describes the Storage Ring RF System and reports about the status of these new developments.

TUPCH143	High Gradient Tests of an 88 MHZ RF Cavity for Muon Cooling	CERN, factory, linac, LEFT	1352
	C. Rossi, R. Garoby, F. Gerigk, J. Marques Balula, M. Vretenar CERN, Geneva
	The scheme for a Muon Cooling channel developed at CERN in the frame of Neutrino Factory studies foresees the use of 44 and 88 MHz cavities operating at a real-estate gradient as high as 4 MV/m. To assess the feasibility of this scheme, including high-gradient operation at relatively low frequency and the production and handling of high RF peak powers, a test stand was assembled at CERN. It included an 88 MHz resonator reconstructed from a 114 MHz cavity previously used for lepton acceleration in the PS, a 2.5 MW final amplifier made out of an old linac unit improved and down-scaled in frequency, and a PS spare amplifier used as driver stage. After only 160 hours of conditioning the cavity passed the 4 MV/m level, with local peak surface field in the gap exceeding 25 MV/m (2.4 times the Kilpatrick limit). The gradient was limited by the amplifier power, the maximum RF peak output power achieved during the tests being 2.65 MW. This paper presents the results of the tests, including an analysis of field emission from the test cavity, and compares the results with the experience in conditioning ion linac RF cavities at CERN.

TUPCH156	Design and Simulation of a Cusp Gun for Gyro-amplifier Application in High Frequency RF Accelerators	electron, gun, cathode, cyclotron	1391
	D.H. Rowlands, A.W. Cross, W. He, A. Phelps, E.G. Rafferty, C.W. Robertson, K. Ronald, J. Thomson, C.G. Whyte, A.R. Young USTRAT/SUPA, Glasgow
	Gyro-amplifiers have potential as the high frequency RF drivers for particle accelerators. They require relativistic electron beams with low velocity spread and with a high fraction of the electron energy associated with the cyclotron motion. For harmonic operation and mode control an axis-encircling beam is desirable. The passage of an electron beam through a non-adiabatic magnetic field reversal (cusp) converts part of the electron beam's axial velocity into axis-encircling transverse velocity. A cusp-based electron beam forming system, yielding a 10MW, 150kV, 70A axis-encircling beam will be presented. This cusp gun is being designed as the electron beam source for a microwave gyro-amplifier that is relevant for high frequency accelerator applications. The latest results from numerical simulations and experiments will be presented and compared.

TUPCH158	High Power, Solid State RF Amplifiers Development for the EURISOL Proton Driver	controls, EURISOL, linac, coupling	1394
	F. Scarpa, A. Facco, D. Zenere INFN/LNL, Legnaro, Padova
	A 5 kW solid-state RF amplifier for the SPES and EURISOL projects has been built and extensively tested. High reliability and low cost are the main goals for this device, an evolution of a 2.5 kW unit previously developed and presented at EPAC 02. The description of the amplifier, especially designed for superconducting cavities, its characteristics and test results will be illustrated and discussed, as well as the design and construction of two new 10 kW amplifier units that have recently started.

TUPCH166	Multi-megawatt Harmonic Multiplier for Testing High-gradient Accelerator Structures	klystron, SLAC, gun, electron	1414
	V.P. Yakovlev Omega-P, Inc., New Haven, Connecticut J.L. Hirshfield Yale University, Physics Department, New Haven, CT
	Basic studies for determining the RF electric and magnetic field limits on surfaces of materials suitable for accelerator structures for a future multi-TeV collider, and for the testing of the accelerator structures and components themselves, require stand-alone high-power RF sources at several frequencies, from 10 to 45 GHz. A relatively simple and inexpensive two-cavity harmonic multiplier at 22.8, 34.3, or 45.7 GHz is suggested to be the stand-alone multi-MW RF power source for this application. The design is based on the use of an existing SLAC electron gun, such as the XP3 gun, plus a beam collector as used on the XP3 klystron. RF drive power would be supplied from an 11.4 GHz, 50 or 75 MW SLAC klystron and modulator, and a second modulator would be used to power the gun in the multiplier. Preliminary computations show that 64, 55, and 47 MW, respectively, can be realized in 2nd, 3rd, and 4th harmonic multipliers at 22.8, 34.3, and 45.7 GHz using 75 MW of X-band drive power.

TUPCH186	Low Level RF System Development for SOLEIL	feedback, SOLEIL, beam-loading, damping	1447
	P. Marchand, M.D. Diop, F. Ribeiro, R.S. Sreedharan SOLEIL, Gif-sur-Yvette M. Luong, O. Piquet CEA, Gif-sur-Yvette
	The Low Level RF system that is used in the SOLEIL storage ring consists in fully analog "slow" amplitude, phase and frequency loops, complemented with a direct RF feedback. A fast digital FPGA-based I/Q feedback, currently under development, will be implemented later on. The performance of both systems has been evaluated using a Matlab-Simulink-based simulation tool. The computed and first experimental results are reported.

TUPCH191	Considerations for the Choice of the Intermediate Frequency and Sampling Rate for Digital RF Control	controls, feedback, laser, DESY	1462
	S. Simrock, M. Hoffmann, F. Ludwig DESY, Hamburg M.K. Grecki, T. Jezynski TUL-DMCS, Lodz
	Modern FPGA-based rf control systems employ digital field detectors where an intermediate frequency (IF) in the range of 10 to more than 100 MHz is sampled with a synchronized clock. Present ADC technology with 14-16 bit resolution allows for maximum sampling rates up to 250 MHz. While higher IF's increase the sensitivity to clock jitter, lower IF frequencies are more susceptible to electromagnetic noise. The choice of intermediate frequency and sampling rate should minimize the overall detector noise, provide high measurement bandwidth and low latency in field detection, and support algorithms for optimal field estimation.

TUPCH193	Low Level RF Control System Modules for J-PARC RCS	controls, acceleration, synchrotron, dipole	1465
	A. Schnase, M. Nomura, F. Tamura, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Yoshii KEK, Ibaraki
	After completing the design phase, the VME modules for the Low Level RF Control (LLRF) of the Rapid Cycling Synchrotron of J-PARC are now in the production and debugging phase. First all modules are tested for basic functionality, for example dual harmonic signal generation. Then sets of modules are connected together to check higher-level functions and feedback. Finally, the LLRF modules are interfaced to high voltage components like amplifiers and cavities. We present the results of these tests, the test methods and test functions on several levels. This way we simulate beam operation working conditions and gain experience in controlling all parameters.

TUPLS002	Dust Macroparticles in HERA and DORIS	electron, vacuum, radiation, storage-ring	1486
	A. Kling DESY, Hamburg
	Charged dust macroparticles are considered as sources of sudden beam lifetime breakdowns detected in many electron storage rings. This phenomenon is still observed in HERA, although the distributed ion pumps, which were previously identified as dust particle sources, have been removed. We report on the observations of trapped dust during the last period of electron operation and present a detailed model of dust macroparticle dynamics in the HERA e-ring and in DORIS with particular emphasis on stability and possible trapping processes.

TUPLS012	Dynamic Stresses in the LHC TCDS Diluter from 7 TeV Beam Loading	LHC, septum, extraction, LEFT	1511
	B. Goddard, A. Presland, W.J.M. Weterings CERN, Geneva L. Massidda CRS4, PULA
	In the event of an unsynchronised beam abort, the MSD extraction septum of the LHC beam dumping system is protected from damage by the TCDS diluter. The simultaneous constraints of obtaining sufficient beam dilution while ensuring the survival of the TCDS make the design difficult, with high thermally induced dynamic stresses occurring in the material needed to attenuate the particle showers induced by the primary beam impact. In this paper, full 3D simulations are described where the worst-case beam loading has been used to generate the local temperature rise and to follow the resulting time evolution of the mechanical stresses. The results and the accompanying design changes for the TCDS, to provide an adequate performance margin, are detailed.

TUPLS029	Optical Scheme of an Electrostatic Storage Ring	quadrupole, storage-ring, lattice, ion	1553
	V. Aleksandrov, Yu. Kazarinov, V. Shevtsov JINR, Dubna, Moscow Region R. Doerner, H. Schmidt-Boecking, K.E. Stiebing IKF, Frankfurt-am-Main A. Schempp IAP, Frankfurt-am-Main
	We consider the optical scheme of an electrostatic storage ring for low energy heavy ions/molecules* with special requirements to type of optical functions. Results of calculation are presented. *C. P. Welsch et al. Proc. of PAC’03, 12-16 May 2003, Portland, Oregon, USA, p.1622.

TUPLS037	The Frankfurt Funneling Experiment	rfq, ion, resonance, ion-source	1574
	U. Bartz, D. Ficek, N. Mueller, A. Schempp, J. Thibus, M. Vossberg IAP, Frankfurt-am-Main
	The goal of the Frankfurt Funneling Experiment is to multiply beam currents of RFQ accelerators at low energies to avoid problems with space charge. The two beams from the ion sources are injected into two RFQ channels. The last part of the RFQ electrodes have been replaced to achieve a 3d focus at the crossing point of the two beam axis where the funneling deflector as a central peace of the experiment is located. The newly designed multi-cell deflector is adapted to the optimised funneling section. It is mechanically solid, easy to tune in and ready for operation. First measurements will be presented.

TUPLS043	Simulations for the Frankfurt Funneling Experiment	emittance, rfq, space-charge, linac	1591
	J. Thibus, A. Schempp IAP, Frankfurt-am-Main
	Beam simulations for the Frankfurt Funneling Experiment are done with RFQSim and FUSIONS. RFQSim is responsible for the beam transport through an RFQ accelerator. Behind the accelerator the particle dynamic program FUSIONS calculates the macro bunches of both beam lines through an r.f. funneling deflector. A new space charge routine has now been included. The status of the development of FUSIONS and the results of the simulations will be presented.

TUPLS044	The 3D Beam Dynamics with the Space Charge in the Low and Middle Energy Super-conducting Option of HIPPI	focusing, emittance, quadrupole, proton	1594
	N.E. Vasyukhin, R. Maier, Y. Senichev, R. Tölle FZJ, Jülich
	For the low and middle energy of the High Intensity Proton Pulse Injector (HIPPI), a superconducting option is considered.The 3D beam dynamics simulation results in the slot and the finger-slot sections covering the energy range from 3 to 160 MeV are presented. The optimization aim is the increase of beam current together with the reduction of emittance growth, beam losses and costs. The slot structure is compared with the conventional spoke structure.

TUPLS049	A Rationale to Design Side Coupled Linac (SCL): a Faster and More Reliable Tool	SCL, coupling, linac, booster	1606
	V.G. Vaccaro, A. D'Elia Naples University Federico II and INFN, Napoli M.R. Masullo INFN-Napoli, Napoli
	A module of an SCL is formed by a cascade of two or more tanks, connected by a Bridge Couplers (BC) with an RF feeder, which realizes a well defined accelerating field configuration in all the coupled cavities. Even resorting to geometrical scaling for the design of the adjacent tanks in the module it is not possible to reproduce the same e-m parameters. In addition to this the BC's for each tanks have a different geometrical design because of phasing constraints. The standard procedure may leads a very slow convergence of the design to the optimum and it is not in general clear if the optimum is reached. In this paper a rationale for designing a module of an SCL will be described and it will be presented its application to PALME first module (30-3???MeV). From a lumped circuit model one may get useful relations between e-m global response of the system and single cell parameters. Therefore it provides a certain number of tools which are used for the designing steps in connection with the standard electromagnetic CAD's, the results of which were used as "measurements".

TUPLS062	Cooling Rates at Ultra-low Energy Storage Rings	electron, ion, storage-ring, antiproton	1633
	C.P. Welsch, C.P. Welsch CERN, Geneva A.V. Smirnov JINR, Dubna, Moscow Region
	Electrostatic low-energy storage rings have proven to be a highly flexible tool, able to cover experiments from a variety of different fields ranging from atomic, nuclear and molecular physics to biology and chemistry. Future machines will decisively rely on efficient electron cooling down to electron energies as low as some eV, posing new challenges to the cooler layout and operation. The BETACOOL code has already been successfully applied for the layout and optimization of a number of different electron coolers around the world. In this contribution, the results from calculations of the cooling rates at future low-energy machines equipped with an internal target like the Ultra-low energy Storage Ring (USR) at the Facility for Low-energy Antiproton and Ion Research (FLAIR) are presented.

TUPLS075	Design of the Flat-top Acceleration Cavity for the LNS Superconducting Cyclotron	resonance, acceleration, cyclotron, extraction	1669
	L.A.C. Piazza, D. Battaglia, L. Calabretta, A.C. Caruso, F. Consoli, M.M. Maggiore, D. Rifuggiato, A. Spartà INFN/LNS, Catania
	A 3rd harmonic Flat-top acceleration system for the K800 Superconducting Cyclotron of the Laboratori Nazionali del Sud (LNS) was designed to reduce the energy spread of the accelerated particles and to improve the beam quality and the extraction efficiency. The Flat-top effect is realized by the superposition of the 3rd harmonic to the fundamental acceleration frequency. The 3rd harmonic frequency is produced by an additional resonator, capacitively coupled to the K 800 cavities. The Flat-top cavity was designed with the 3D electromagnetic codes Ansoft HFSS and CST MicroWaveStudio.

TUPLS077	Development of FFAG-ERIT Ring	target, proton, storage-ring, emittance	1675
	K. Okabe, M. Muto KEK, Ibaraki Y. Mori KURRI, Osaka
	An intense neutron source with the emittance recovery internal target (ERIT) using the FFAG accelerator is under development. The design of the FFAG storage ring for this purpose will be presented.

TUPLS078	Design Studies of the Compact Superconducting Cyclotron for Hadron Therapy	cyclotron, ion, injection, extraction	1678
	Y. Jongen, W. Beeckman, W.J.G.M. Kleeven, D. Vandeplassche, S.E. Zaremba IBA, Louvain-la-Neuve V. Aleksandrov, G.A. Karamysheva, Yu. Kazarinov, I.N. Kian, S.A. Kostromin, N.A. Morozov, E. Samsonov, V. Shevtsov, G. Shirkov, E. Syresin JINR, Dubna, Moscow Region
	An overview of the current status of the design of the compact superconducting isochronous cyclotron C400 able to deliver ion beams with a charge to mass ratio of 0.5 is given. This cyclotron is based on the design of the current PT (proton therapy) C230 cyclotron and will be used for radiotherapy with proton, helium or carbon ions. 12C⁶⁺ and 4He²⁺ ions will be accelerated to 400 MeV/u energy and extracted by electrostatic deflector, H²⁺ ions will be accelerated to the energy 260MeV and extracted by stripping. Computer modeling results on the axial injection system, magnetic system, inflector and center design are given. Results of simulations of the ion beam injection, acceleration and extraction are presented.

TUPLS085	Stacking Simulations in the Beta-beam Decay Ring	ion, injection, CERN, collimation	1699
	S. Hancock CERN, Geneva A. Chancé CEA, Gif-sur-Yvette
	The so-called beta-beam concept for accelerator-driven neutrino experiments envisages the production of a pure beam of electron neutrinos (or their antiparticles) through the beta-decay of radioactive ions circulating in a high-energy storage ring. An unprecedented number of ions must be collected in the decay ring and maintained in a few short bunches. Stacking is unavoidable to match the available source rates with this demand. A new stacking method makes use of off-momentum injection into the decay ring to approach the circulating beam without requiring ultra-fast injection elements, rotation in the longitudinal plane to bring the fresh bunches onto the central orbit and asymmetric merging to transport these ions into the centre of the large stack. Simulation results are presented for the complete repetitive stacking process for two candidate ion species of significantly different charge-to-mass ratio.

TUPLS090	LEBT Simulations and Ion Source Beam Measurements for the Front End Test Stand (FETS)	ion, emittance, ion-source, space-charge	1714
	S. Jolly, P. Savage Imperial College of Science and Technology, Department of Physics, London J.J. Back University of Warwick, Coventry D.C. Faircloth, A.P. Letchford CCLRC/RAL/ISIS, Chilton, Didcot, Oxon J.K. Pozimski CCLRC/RAL, Chilton, Didcot, Oxon
	The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) is intended to demonstrate the early stages of acceleration (0-3MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories. Optimisation of the beam focussing within the Low Energy Beam Transport (LEBT) is necessary to minimise beam losses upon acceleration within the FETS RadioFrequency Quadrupole (RFQ). Simulations of the LEBT are currently under way using the General Particle Tracer package (GPT). Previous envelope calculations suggest weak and strong focussing solutions for the LEBT solenoids. Definitive beam dynamics simulations in GPT require further measurements of the transverse emittances and beam profile of the ion source beam, due to the sensitivity of the simulations on the initial beam profile and level of space charge compensation. A pepperpot emittance/profile measurement system has been designed for use on the ISIS ion source development rig. Results from this pepperpot system are used to constrain the initial conditions for the GPT simulations.

TUPLS092	Implementations on the RF Charge Breeder Device BRIC with Test Measurements	ion, MCP, electron, extraction	1717
	V. Variale, A. Boggia, T. Clauser, A.C. Rainò, V. Valentino INFN-Bari, Bari P.A. Bak, G.I. Kuznetsov, B.A. Skarbo, M.A. Tiunov BINP SB RAS, Novosibirsk
	The Radioactive Ion Beam (RIB) production with ISOL technique should require a charge breeder device to increase the ion acceleration efficiency and reduce greatly the production cost. The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept RIB with charge state +1 and increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds and it has been assembled at the LNL (Italy) laboratory. BRIC could be considered as a solution for the charge state breeder of the SPES project under study also at the LNL. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) - Quadrupole aiming to filtering the unwanted masses and then making a more efficient containment of the wanted ions. The RF test measurements seem confirm, as foreseen by simulation results* that a selective containment can be obtained. Most accurate measurements, however, are needed and for that implementations of the system have been carried out. *V. Variale and M. Claudione. "BRICTEST: a code for charge breeding simulations in RF quadrupolar field", NIM in Phys. res. A 543 (2005) 403-414.

TUPLS104	Matching of High Intensity Ion Beams to an RFQ: Comparison of PARMTEQ and IGUN Simulations	rfq, ion, emittance, ion-source	1741
	R. Becker, R.A. Jameson IAP, Frankfurt-am-Main
	The classical way of matching an ion source to the low energy accelerator RFQ generally is performed by adjusting the matching optics of the LEBT to provide the rms ellipse twiss parameter requirements of the RFQ shaper section. By matching to the rms parameters (the equivalent rms beam method) the actual shape of the distribution plays a smaller role according to F. Sacherer. In many cases, however, the matching optics are creating not only aberrations to the ion beam but also a very non-elliptical shape of the emittance figure, and a more exact match may be required. As a way out, an ion extraction program (IGUN) has been modified to also take into account the rf-focusing of non-modulated RFQ vanes in the shaper section. This makes it feasible to use this program for the simulation from the ion source plasma until the beginning of modulation inside the RFQ, and it can also handle dc fields in the injection region of the RFQ. In order to demonstrate the differences of both approaches we apply them to well defined experimentally proved designs of RFQ shaper sections.

TUPLS106	Pulsed Bending Magnet of the J-PARC MR	power-supply, TESLA, synchrotron, KEK	1747
	K. Koseki, H. Kobayashi, H. Nakayama, K.O. Okamura, M.J. Shirakata, M. Tawada KEK, Ibaraki
	Japan Proton Accelerator Research Complex (J-PARC) is under construction with a collaboration between Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK). The J-PARC consists of a 180 MeV linac, a 3 GeV rapid-cycle synchrotron (RCS) and a 50 GeV synchrotron (MR). The bunch trains, which extracted from the RCS, is delivered both to the “Materials and Life Science Facility” and to the MR, two beam transport lines, 3-NBT and 3-50BT, are constructed. The switching of bunch trains is performed by a pulsed bending magnet. The field strength of 1.21 Tesla with rise and fall time of less than 40 msec is required. It was found that an effect induced by eddy current, which flows at thick end-plates, disturbs the flatness of the magnetic field. A simple compensation circuit has been adopted for a cure. A result from a field measurement, which shows a sufficient flatness, is presented.

TUPLS109	Present Status of the L3BT for J-PARC	injection, emittance, quadrupole, linac	1756
	T. Ohkawa JAEA, Ibaraki-ken M. Ikegami KEK, Ibaraki J. Qiang LBNL, Berkeley, California
	L3BT is a beam transport line from J-PARC (Japan Proton Accelerator Research Complex) linac to the succeeding 3-GeV RCS (Rapid Cycling Synchrotron). The construction of the L3BT has been almost finished. The beam commissioning of the L3BT will be started soon. On the other hand we have performed 3D particle simulations with PARMILA and IMPACT to evaluate the performance of the halo scraping, momentum compaction and beam diagnostics. In this paper, results of the beam simulation of the L3BT are presented. The construction status of the L3BT is also presented in brief.

TUPLS115	Transverse Phase Space Painting for the CSNS Injection	injection, emittance, space-charge, lattice	1774
	J. Qiu, J. Tang, S. Wang IHEP Beijing, Beijing J. Wei BNL, Upton, Long Island, New York
	The CSNS accelerators consist of an 80 MeV proton Linac, and a 1.6 GeV rapid cycling synchrotron (RCS). The ring accumulates 1.88*1013 protons via H－stripping injection in the phase CSNS-I. The injected beam is painted into the large transverse phase space to alleviate space-charge effects. The uniformity of beam emittance is important in reducing the tune shift/spread due to space charge effect. The paper introduces two parameters to evaluate the uniformity of a distribution. To satisfy the low-loss design criteria, extensive comparison of different painting scenarios has been carried out by using the simulation code ORBIT. This paper gives detailed studies on painting schemes and the dependence on the lattice tune, the injection peak current, and also chopping rate.

TUPLS126	Interaction of the CERN Large Hadron Collider (LHC) Beam with Carbon Collimators	LHC, target, proton, heavy-ion	1798
	N.A. Tahir, D. Hoffmann GSI, Darmstadt Y. Kadi, R. Schmidt CERN, Geneva R. Piriz Universidad de Castilla-La Mancha, Ciudad Real A. Shutov IPCP, Chernogolovka, Moscow region
	The LHC will operate at 7 TeV with a luminosity of 10³⁴ cm-2s-1. Each beam will have 2808 bunches, with nominal intensity per bunch of 1.1x10¹¹ protons. The energy stored in each beam of 362 MJ. In a previous paper the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected into a copper target. Another failure scenario is the deflection of beam into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC to diffuse or absorb beam losses. Since their jaws are close to the beam, it is very likely that they are hit first when the beam is accidentally deflected. Here we present the results of two-dimensional hydrodynamic simulations of the heating of a solid carbon cylinder irradiated by the LHC beam with nominal parameters, carried out using the BIG-2 computer code* while the energy loss of the 7 TeV protons in carbon is calculated using the well known FLUKA code*. Our calculations suggest that the LHC beam may penetrate up to 10 m in solid carbon, resulting in a substantial damage of collimators and beam absorbers. V. E. Fortov et al. Nucl. Sci. Eng. 123 (1996) 169. **A. Fasso et al. The physics models of FLUKA: status and recent development, CHEP 2003, La Jolla, California, 2003.

TUPLS127	Permanent Deformation of the LHC Collimator Jaws Induced by Shock Beam Impact: an Analytical and Numerical Interpretation	LHC, CERN, proton, collimation	1801
	A. Bertarelli, O. Aberle, R.W. Assmann, A. Dallocchio, T. Kurtyka, M. Magistris, M. Mayer, M. Santana-Leitner CERN, Geneva
	Inspections carried out on jaws of the LHC collimator prototype, which underwent the 450 GeV robustness test in CERN TT40 extraction line, revealed no visible damage, except a permanent deformation of the jaw metal support of ~300 um. An explanation of this phenomenon is proposed in this paper. The temperature increase on the metal support induced by the thermal shock, though limited to ~70°C, led to a sudden expansion of the copper-based support which was partially prevented by the inertia of the material itself, thus generating compressive stresses exceeding the elastic limit of OFE-copper. An analytical assessment of the process, followed by a finite-element transient elasto-plastic analysis, is presented. Numerical results are in good agreement with measured data. In order to confirm this analysis, a special test on series production jaws, where OFE-copper has been replaced by Dispersion Strengthened Copper (Glidcop�), is scheduled for the second half of 2006.

TUPLS128	A New Analytical Method to Evaluate Transient Thermal Stresses in Cylindrical Rods Hit by Proton Beams	target, proton, CERN, LHC	1804
	A. Dallocchio, A. Bertarelli, T. Kurtyka CERN, Geneva
	This paper presents an analytical solution for the thermo-mechanical problem of CNGS target rods rapidly heated by fast extracted high energy proton beams. The method allows the computation of the dynamic transient elastic stresses induced by a proton beam hitting off-axis the target. The studies of such dynamic thermo-mechanical problems are usually made via numerical methods. However, an analytical approach is also needed to quickly provide reference solutions for the numerical results. An exact solution for the temperature field is first obtained, using Fourier-Bessel series expansion. Quasi-static thermal stresses are then computed as a function of the calculated temperature distribution, making use of the thermoelastic displacement potential for the equivalent isothermal two-dimensional stress problem. Finally, the contribution of dynamic stresses due to longitudinal and bending stress waves is determined by means of the modal summation method. This method can be effectively applied to any solid having cylindrical shape, made out of isotropic elastic material.

TUPLS130	Comparison between Measured and Simulated Beam Loss Patterns in the CERN SPS	SPS, LHC, beam-losses, proton	1810
	S. Redaelli, G. Arduini, R.W. Assmann, G. Robert-Demolaize CERN, Geneva
	A prototype of an LHC collimator has been tested with proton beams at the CERN SPS. The interaction of the circulating proton beam with the carbon collimator jaws generated showers that were lost in the downstream SPS aperture. The measured beam loss patterns are compared in detail with the results of dedicated loss simulations. The simulation package includes (1) a 6D particle tracking through the SPS lattice; (2) the scattering interaction of protons with the collimator jaw material; (3) the time-dependent displacement of the collimator jaws with respect to the beam orbit; (4) a detailed aperture model of the full SPS ring. It is shown that the simulation tools can reliably predict the measured location of losses. This provides an important assessment of the simulation tools in view of the LHC beam loss studies.

TUPLS132	Estimation of the Energy Deposited on the CNGS Magnetic Horn and Reflector	target, shielding, focusing, secondary-beams	1813
	L. Sarchiapone, A. Ferrari, M. Lorenzo Sentis CERN, Geneva
	In the CNGS installation two magnetic lenses, namely the horn and the reflector, focus the secondary beam generated in the target station. The gap between the horn and reflector is chosen to optimize a wide-band high-energy muon-neutrino beam. These two focusing elements are two coaxial lenses similar in length but different in shape: the outer conductor has a cylindrical shape whereas the inner conductor consists of a sequence of conical shapes to optimize the focusing capacity. The evaluation of the heat load on the support structures is crucial since modifications in the elements around the horn and reflector are under way and the support structures can be adapted to the heat load found. Furthermore, the heat load in the whole horn area has been evaluated to optimize the cooling-ventilation system. The FLUKA geometry input of the horn and reflector electrical connections has been notably improved in order to accommodate the detailed striplines design to the thermal expansion. The energy deposited on the horn and reflector as well as on their adjacent elements has been estimated using the FLUKA Monte Carlo package and results are presented in this document.

TUPLS136	Air Temperature Analysis and Improvement for the Technical Zone at TLS	controls, vacuum, storage-ring, power-supply	1825
	J.-C. Chang, J.-R. Chen, Z.-D. Tsai NSRRC, Hsinchu M. Ke NTUT, Taipei
	This paper presents the air temperature analysis and control improvement for the technical zone, where many critical instrumentations of power supply, rf, vacuum and control apparatuses are located, at the Taiwan Light Source (TLS). The technical zone with circular shape is located on the core area of the storage ring. The diameter and height of the technical zone are 28.5m and 3m, respectively. Totally 13 temperature sensors are installed in this zone to online record the air temperature history. Because of insufficient cooling capacity and poor air circulation of the air-conditioning (A/C) system, the air temperature may reach to 30 degrees C, and spatial air temperature difference may be more than 7 degrees C. To cope with those problems, a computational fluid dynamics (CFD) code is applied to simulate the spatial temperature distribution. The A/C cooling capacity will be increased, and the air exit and exhaust distribution will be modified according to the simulated results.

WEOBPA03	1.8 MW Upgrade of the PSI Proton Facility	cyclotron, target, extraction, space-charge	1879
	P.A. Schmelzbach, S.R.A. Adam, A. Adelmann, H. Fitze, G. Heidenreich, J.-Y. Raguin, U. Rohrer, P.K. Sigg PSI, Villigen
	The PSI proton accelerator delivers currently a 590 MeV beam with an intensity of 2 mA. The upgrade programme aiming at boosting the beam power from 1.2 to 1.8 MW includes the ongoing installation of new bunchers in the transfer lines to the injector cyclotron and between injector and ring cyclotron, the replacement of the Al-cavities of the ring cyclotron by Cu-cavities operated at 1 MV, and the design and future installation of additional accelerating cavities in the injector cyclotron. Simulation studies are under way to improve our understanding of the space charge effects at the different stages of acceleration. The present status of the project will be presented.
	Transparencies

WEXFI01	Instabilities and Space Charge Effects in High Intensity Ring Accelerators	space-charge, damping, impedance, dipole	1882
	O. Boine-Frankenheim, I. Hofmann, V. Kornilov GSI, Darmstadt
	This presentation will review beam dynamics in circular accelerators with high beam intensity and space charge effects. The main focus will be on recent theoretical and experimental results related to collective instabilities and resonance crossing with space charge. In the first part of the presentation, the effect of space charge on collective instability thresholds and impedance budgets will be discussed. In this context the effect of space charge induced mode coupling on the longitudinal microwave instability will be illustrated. The stability of longitudinal bunched beam modes and of transverse dipole modes in the presence of space charge will be discussed. Recent work related to the transverse mode coupling instability (TMCI) with space charge will be reviewed. In the second part of the presentation, "incoherent" space charge effects on transverse nonlinear dynamics issues, like nonlinear resonance crossing, will be reviewed.
	Transparencies

WEYFI01	Modelling of Space Charge and CSR Effects in Bunch Compressor Systems	CSR, space-charge, emittance, radiation	1897
	M. Dohlus DESY, Hamburg
	Bunches with high peak currents of the order of kilo-Amperes are required in linac based X-ray free electron lasers. These bunches cannot be produced directly in guns because space charge forces would destroy the brilliance within a short distance. Therefore bunches with a peak current of a few tens of Amperes are created in laser-driven radio-frequency sources and are compressed in length by two orders of magnitude. In most designs, the compression is achieved in magnet chicanes, where particles with different energies have different path lengths so that a bunch with an energy distribution correlated with longitudinal particle position can shrink in length. The principle problem is that short bunches on curved trajectories will emit coherent synchrotron radiation (CSR). The CSR effects and the space charge fields play an important role in the particle dynamic and the design of a bunch compression system. This presentation will provide an overview of computational methods and simulation tools for space charge and coherent synchrotron radiation effects in magnetic bunch compression systems.
	Transparencies

WEOFI03	Beam Dynamics Simulation in e^- Rings in SRFF Regime	CSR, vacuum, lattice, synchrotron	1908
	L. Falbo INFN-Pisa, Pisa D. Alesini INFN/LNF, Frascati (Roma) M. Migliorati Rome University La Sapienza, Roma
	The concept of strong RF focusing has been recently proposed to obtain locally short bunches in electron/positron colliders, by modulating the longitudinal bunch dimensions along the rings. To study the single bunch dynamics, a macroparticle numerical code has been written which simulates the effects of the objects generating broad band impedance along the ring and the effects of the coherent synchrotron radiation in dipoles and wigglers. The obtained results are shown and discussed.
	Transparencies

WEPCH006	Comparison between Simulations and Measurements of Low Charge Electron Bunch in the ELSA Facility	laser, electron, quadrupole, ELSA	1927
	J.-L. Lemaire, A.B. Binet, A.B. Bloquet, D. Guilhem, V. Le Flanchec, S. Pichon CEA, Bruyeres-le-Chatel
	Dedicated focal spot size measurements carried out at the ELSA electron linear accelerator facility have provided detailed data which are suitable for benchmarking of different simulation codes for high charge bunch beam acceleration issued from an RF photo-injector source. We present some characteristic features of bunched electron beam propagation from beam formation at the photo-cathode to acceleration through RF cavities until the final focussing on a target, by using numerical simulations obtained with MAGIC, PARMELA, MAFIA, PARTRAN tool box codes. The challenges for the planned benchmarking are discussed.

WEPCH015	Measurement and Correction of Dispersion in the VUV-FEL	undulator, quadrupole, DESY, electron	1951
	E. Prat, W. Decking, T. Limberg DESY, Hamburg
	Increase in transverse beam size in the undulator caused by dispersive effects is one of the major limitations for the operation of FLASH, the VUV-FEL at DESY. Sources of the (spurious) dispersion are field errors and stray magnet fields in the undulator beam line as well as spurious dispersion created upstream of the undulator by, for instance, rf coupler kicks, magnet misalignments and field errors. The impact of these errors on dispersion generation depends on the actual operating conditions of the accelerator, so the dispersion must be measured and controlled frequently. In this paper we present numerical studies of spurious dispersion generation, first dispersion measurements and correction results.

WEPCH017	Front-to-end Simulation of the Injector Linac for the Heidelberg Ion Beam Therapy Centre	ion, linac, rfq, quadrupole	1957
	R. Cee HIT, Heidelberg C.M. Kleffner, M.T. Maier, B. Schlitt GSI, Darmstadt U. Ratzinger, A. Schempp IAP, Frankfurt-am-Main
	The injector linac of the Heidelberg ion beam therapy centre is currently in the commissioning phase. Its main components are two electron cyclotron resonance ion sources (ECRIS), a radio-frequency quadrupole accelerator (RFQ) and an interdigital H-type drift tube linac (IH-DTL). It will be able to accelerate beams of hydrogen-, helium-, carbon- and oxygen-ions up to a specific energy of 7 MeV per nucleon. This contribution focuses on the beam dynamics simulation of the transport lines and the accelerating structures. Three dedicated tools have been employed: Mirko for the beam transport, RFQmed for the particle dynamics through the RFQ and LORASR for the acceleration in the IH-DTL. Between the different beam dynamics codes interfaces have been implemented and a front-to-end simulation has been performed. Comparisons with alternative programmes confirm the results obtained. The work will enable us to investigate the behaviour of the machine in a theoretical model during the forthcoming operating.

WEPCH020	Extending the Linear Least Squares Problem for Orbit Correction in Circular Accelerators	controls, ELETTRA, feedback, insertion	1963
	C. Scafuri ELETTRA, Basovizza, Trieste
	A method for extending the linear least squares problem applicable for correcting the orbit of circular accelerators is proposed. The method is based on the definition of a suitable cost function which weighs both orbit deviations and the correction effort, that is steerer kicks. The paper presents the full derivation of the formulas and the results of simulations. The application of this method for the Global Orbit Feedback system of the ELETTRA storage ring is being evaluated.

WEPCH025	COD Correction at the PF Ring by New Orbit Feedback Scheme	feedback, insertion, insertion-device, electron	1978
	K. Harada, T. Obina KEK, Ibaraki N. Nakamura, H. Sakai, H. Takaki ISSP/SRL, Chiba
	When we correct the global COD (closed orbit distortion), if we use the modified conversion matrix calculated by the eigen vector method with constraint conditions (EVC), the local orbit correction can be simultaneously done to fix the light source point in the insertion device. In the EVC, the local orbit correction is combined to the global orbit correction by the Lagrange's undetermined multiple method. In this paper, we show the machine study results at the PF Ring.

WEPCH045	Sorting Strategies for the Arc Quadrupoles of the LHC	LHC, quadrupole, optics, resonance	2017
	Y. Papaphilippou, A.M. Lombardi CERN, Geneva
	The variation in the field gradient of the LHC arc quadrupoles can not be corrected independently by the dedicated trim quadrupole circuits. This may result to a beta function beating larger than the one accepted by the machine budget. In this respect, sorting strategies for the installation of these magnets were implemented in order to eliminate this effect, as locally as possible. Special care was taken for quadrupoles whose warm measurements showed large gradient errors due to an excessive magnetic permeability. The figures of merit used in the sorting and the results obtained for all 8 sectors of the LHC are detailed. The global optics function beating foreseen, as computed by both analytical estimates and simulations with MAD-X are finally presented.

WEPCH047	Procedures and Accuracy Estimates for Beta-beat Correction in the LHC	LHC, quadrupole, coupling, power-supply	2023
	R. Tomas, O.S. Brüning, S.D. Fartoukh, M. Giovannozzi, Y. Papaphilippou, F. Zimmermann CERN, Geneva R. Calaga, S. Peggs BNL, Upton, Long Island, New York F. Franchi GSI, Darmstadt
	The LHC aperture imposes a tight tolerance of 20% on the maximum acceptable beta-beat in the machine. An accurate knowledge of the transfer functions for the individually powered insertion quadrupoles and techniques to compensate beta-beat are key prerequisites for successful operation with high intensity beams. We perform realistic simulations to predict quadrupole errors in LHC and explore possible ways of correction to minimize beta-beat below the 20% level.

WEPCH079	Effects of Intrinsic Nonlinear Fields in the J-PARC RCS	resonance, sextupole, space-charge, injection	2104
	H. Hotchi, Y. Irie, F. Noda JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon A.Y. Molodozhentsev KEK, Ibaraki
	In order to accelerate a high intense proton beam with small particle losses, the J-PARC RCS, which is being constructed at JAEA, has a large acceptance. In such synchrotrons, the nonlinear motion of the beam particles, especially moving away from the axis of the elements, is a common issue, and it becomes essential to consider intrinsic field nonlinearities. The main sources of nonlinear magnetic fields in the RCS are as follows: fringes of the main dipole and quadrupole magnets, sextupole fields used for the chromatic correction, leak fields from the injection and extraction beam lines, etc. In this paper, we will discuss influences of the intrinsic field nonlinearities and a cure for the induced betatron resonances, based on single-particle and multi-particle tracking simulations.

WEPCH080	Beam Simulation of SQQ Injection System in KIRAMS-30 Cyclotron	cyclotron, injection, ion-source, space-charge	2107
	D.H. An, J.-S. Chai, H.B. Hong, S.S. Hong, M.G. Hur, W.T. Hwang, H.S. Jang, I.S. Jung, J. Kang, J.H. Kim, Y.S. Kim, M.Y. Lee, T.K. Yang KIRAMS, Seoul
	The injection system of KIRAMS-30 cyclotron consists of a double gap buncher, an SQQ, and a spiral inflector. Initial beam with 100 mmmrad has been generated by random Gaussian function in the transverse plane and random uniform function in the longitudinal direction. Using the 3D electric and magnetic fields of a buncher, SQQ, inflector, and return-yoke bore, the characteristics of the beam injected into the KIRAMS-30 cyclotron's central region has been obtained. This paper presents the results of its beam characteristics and parameters of each beam element.

WEPCH081	Injection of The Proton Beam Into The Compact Cyclotron with Solenoid	cyclotron, injection, emittance, space-charge	2110
	L.M. Onischenko, E. Samsonov JINR, Dubna, Moscow Region
	The proton (H-) low (100 mkA) intensity beam injected by means of the solenoid comes to the first cyclotron orbit without the beam emittance deterioration. This is demonstrated by computer simulation.

WEPCH088	High Order Aberration Correction	controls, multipole, background, quadrupole	2125
	S.N. Andrianov St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg A.N. Chechenin FZJ, Jülich
	It is known that modern accelerators fall under nonlinear aberrations influence. The most of these aberrations have harmful character, and their effect must be maximally decreased. There are a set of approaches and codes to solving this problem. In this paper, we consider an approach for solving this problem using the matrix formalism for Lie algebraic tools. This formalism allows reducing the starting problem to linear algebraic equations for aberration coefficients, which are elements of corresponding matrices. There are discussed results evaluated using suggested approach and nonlinear programming tools. Some examples of corresponding results are given.

WEPCH092	Dynamical Aperture Studies for the CERN LHC: Comparison between Statistical Assignment of Magnetic Field Errors and Actual Measured Field Errors	LHC, quadrupole, optics, dipole	2128
	M. Giovannozzi, S.D. Fartoukh, S.S. Gilardoni, J.-B. Jeanneret, A.M. Lombardi, Y. Papaphilippou, T. Risselada, R. de Maria CERN, Geneva
	It is customary to evaluate the performance of a circular particle accelerator by computing the dynamical aperture, i.e., the domain in phase space where bounded single-particle motion occurs. In the case of the LHC the dynamical aperture computation is performed by assuming a statistical distribution of the magnetic field errors of various magnets' classes: the numerical computations are repeated for a given set of realisations of the LHC ring. With the progress in the magnet production and allocation of the available positions in the ring, the statistical approach has to be replaced by the computation of one single configuration, namely the actual realisation of the machine. Comparisons between the two approaches are presented and discussed in details.

WEPCH093	Parameter Scans and Accuracy Estimates of the Dynamic Aperture of the CERN LHC	LHC, dynamic-aperture, CERN, dipole	2131
	M. Giovannozzi, E. McIntosh CERN, Geneva
	Techniques to make use of large distributed computing facilities allow for denser parameter scans of the dynamical aperture, i.e., the domain in phase space where bounded single-particle motion prevails. Moreover, one can also increase the number of 'seeds' each of which represents a possible realisation of multipolar components around the machine. In this paper the dependence of the dynamical aperture on the step size of the grid of initial conditions and on the number of seeds is studied. Estimates on the accuracy of the dynamic aperture are derived and the definition of an improved protocol for numerical simulations is presented.

WEPCH095	Models to Study Multi-bunch Coupling through Head-on and Long-range Beam-beam Interactions	coupling, damping, LHC, CERN	2137
	T. Pieloni, W. Herr CERN, Geneva
	In the LHC almost 6000 bunches will collide in four interaction points where they experience head-on as well as clustered long range interactions. These lead to a coupling between all bunches and coherent beam-beam effects. For two colliding bunches this is well understood. However, for a large number of bunches colliding with different collision patterns, it results in a complex spectrum of oscillation frequencies with consequences for beam measurements and Landau damping. To study the coherent beam-beam modes, three complementary models have been developped and will be described in this report. Two of these methods rely on self-consistent multi-bunch and multi-particle tracking while the third is a semi-analytic model based on a complex matrix algorithm. The three methods together provide useful information about the beam-beam coupling of multi bunch beams and together provide a deeper insight into the underlying physics.

WEPCH097	Beam Dynamics in Compton-ring Gamma Sources	laser, electron, synchrotron, emittance	2143
	E.V. Bulyak, P. Gladkikh, V. Skomorokhov NSC/KIPT, Kharkov K. Moenig DESY Zeuthen, Zeuthen T. Omori, J. Urakawa KEK, Ibaraki F. Zimmermann CERN, Geneva
	Electron storage rings with a laser cavity are promising intensive sources of polarized hard photons to generate polarized positron beams. The dynamics of electron bunches circulating in a storage ring and interacting with high-power laser pulses is studied both analytically and by simulation. Common features and difference in the bunch behavior interacting with an extremely high power laser pulse (polarized positron source for the ILC project) and a moderate pulse (source for CLIC) are shown. Also considerations on particular lattice designs for both rings are presented.

WEPCH102	Studies of the Nonlinear Dynamics Effects of APPLE-II Type EPUs at the ALS	polarization, dynamic-aperture, multipole, lattice	2152
	C. Steier, S. Marks, S. Prestemon, D. Robin, D. Schlueter, W. Wan, W. Wittmer LBNL, Berkeley, California
	Elliptically Polarizing Undulators (EPUs) have become more and more popular at synchrotron radiation sources, providing full polarization control of the photon beam. The fields of the most commonly used APPLE-II type EPUs have a very fast, intrinsic field roll-off, creating significant non-linearities of the beam motion with in some cases large impact on the dynamic (momentum) aperture. In general, the nonlinear effects get stronger with longer periods and higher undulator magnetic fields. One of the planned future beamlines at the ALS (MERLIN) will use a quasiperiodic EPU with 9 cm period and maximum B fields of about 1.3 T. We will present simulation studies for the proposed shimming schemes for this future device to reduce the nonlinear effects to acceptable values, as well as experimental studies for the existing 5 cm period EPUs already installed in the ALS.

WEPCH104	Observation of the Long-range Beam-beam Effect in RHIC and Plans for Compensation	RHIC, LHC, beam-losses, emittance	2158
	W. Fischer, R. Calaga BNL, Upton, Long Island, New York U. Dorda, J.-P. Koutchouk, F. Zimmermann CERN, Geneva A.C. Kabel SLAC, Menlo Park, California J. Qiang LBNL, Berkeley, California V.H. Ranjibar, T. Sen Fermilab, Batavia, Illinois J. Shi KU, Lawrence, Kansas
	At large distances the electromagnetic field of a wire is the same as the field produced by a bunch. Such a long-range beam-beam wire compensator was proposed for the LHC, and single beam tests with wire compensators were successfully done in the SPS. RHIC offers the possibility to test the compensation scheme with colliding beams. We report on measurements of beam loss measurements as a function of transverse separation in RHIC at injection, and comparisons with simulations. We present a design for a long-range wire compensator in RHIC.

WEPCH107	Contributors to AIRIX Focal Spot Size	target, ion, emittance, electron	2164
	N. Pichoff, M. Caron, F. Cartier, D.C. Collignon, A. Compant La Fontaine, G. Grandpierre, L.H. Hourdin, M. Mouillet, D.P. Paradis CEA, Bruyères-le-Châtel
	High intensity electron beam focusing is a key issue for the successful development of flash radiography at hydro test facilities. AIRIX is a 2 kA, 19 MeV, 60 ns, single shot linear accelerator that produces X-rays from the interaction between relativistic electrons and a Tantalum solid target (Ta). A simulation tool has been developed to model the pulsed-beam dynamics through the accelerator from the cathode to the target. This simulator has allowed to estimate the contribution to the beam size on the target (focal spot) of beam emittance, pulse energy dispersion, pulse rising and falling fronts and the ion production on the target. The quantified contributions of these phenomena are reviewed here.

WEPCH109	Comprehensive Benchmark of Electromagnetic 3D Codes in Time and Frequency Domain	impedance, damping, ESRF, vacuum	2167
	V. Serriere, N. Guillotin, J. Jacob ESRF, Grenoble F. Marhauser, E. Weihreter BESSY GmbH, Berlin
	A comprehensive benchmark of todays most powerful numerical 3D Eigenmode and Time Domain Solvers has been performed using the input geometry of a HOM-damped cavity and a highly lossy waveguide load developed at BESSY. The paper details the simulations results together with existing experimental data.

WEPCH112	Database Extension for the Beam Dynamics Simulation Tool V-code	quadrupole, gun, electron, multipole	2176
	W. Ackermann, W.F.O. Müller, B. Steiner, T. Weiland TEMF, Darmstadt J. Enders, H.-D. Gräf, A. Richter TU Darmstadt, Darmstadt
	The beam dynamics simulation tool V-Code has been proved to be very useful in redesigning the injector layout at the superconducting linear accelerator in Darmstadt (S-DALINAC). Modifications in the beam optics are necessary because a new source of polarized electrons should be installed in addition to the existing thermionic gun. The calculations are performed with V-Code which is designed to handle a large amount of individual beam line elements and can therefore be used for extensive accelerator studies. The available database includes all the necessary components like solenoids, quadrupoles and rf cavities, but as a result of their consecutive treatment overlapping external fields are not allowed. Due to geometrical restrictions in the assembly of the new source a space-saving candidate of a quadrupole triplet violates this software-related condition if it is regarded as three distinct quadrupoles. Consequently, a more general beam line element has to be created which treats the lenses as a single unit without interference of their fields to attached cells. The indispensable data base extension together with simulation results and implementation verifications will be presented.

WEPCH113	Numerical Impedance Calculations for the GSI SIS-100/300 Kickers	kicker, impedance, coupling, injection	2179
	B. Doliwa, H. De Gersem, T. Weiland TEMF, Darmstadt
	Fast kicker modules represent a potential source for beam instabilities in the planned Facility for Antiproton and Ion Research (FAIR) at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. In particular, the more than fifty kicker modules to be installed in the SIS-100 and SIS-300 synchrotrons are expected to have a considerable parasitic influence on the high-current beam dynamics. Here we present our numerical investigations of the longitudinal and transverse kicker coupling impedances using a specialized electromagnetic field software. Besides the coupling to the external network, particular attention is paid to the question whether a resistively-coated ceramic beam pipe is able to reduce coupling impedances and ferrite heating significantly.

WEPCH114	On the Development of a Self-consistent Particle-in-cell (PIC) Code Using a Time-adaptive Mesh Technique	gun, PITZ, DESY, ASTRA	2182
	S. Schnepp, E. Gjonaj, T. Weiland TEMF, Darmstadt
	For a large class of problems the self-consistent simulation of charged particle beams in linear accelerators is necessary. Especially, in all low-energetic sections such as injectors the self-consistent interaction of particles and fields has to be taken into account. Well-known programs like the MAFIA TS Modules typically use the Particle-in-cell (PIC) method for beam dynamics simulations. Since they use a fixed computational grid which has to resolve the bunch adequately, they suffer from enormous memory consumption. Therefore and especially in the 3D case, only rather short sections can be simulated. A remedy to this limitation is the usage of a grid which refines itself in the vicinity of particles. For this purpose, a new code called SMOVE based on a time-adaptive grid is being developed. First promising results will be presented at the conference.

WEPCH115	Numerical Simulation and Optimization of a 3-GHz Chopper/Prebuncher System for the S-DALINAC	electron, impedance, MAMI, acceleration	2185
	N. Somjit, W.F.O. Müller, T. Weiland TEMF, Darmstadt R. Eichhorn, J. Enders, H.-D. Gräf, C. Heßler, Y. Poltoratska, A. Richter TU Darmstadt, Darmstadt
	A new source of polarized electrons with an energy of 100 keV is presently being developed at the superconducting Darmstadt electron linear accelerator S-DALINAC for future nuclear- and radiation-physics experiments. The pulsed electron beam emitted by the photocathode will be cut to 50 ps by a chopper operated at 3 GHz, and further bunch compression down to 5 ps will be achieved by a two-stage prebuncher section. The chopper-prebuncher system is based on similar devices used at the Mainz Mikrotron (MAMI) where the accelerator frequency is slightly smaller (2.4 GHz). For the chopper, a cylindrical resonator operating at TM110 mode is selected to deflect the electron beam onto an ellipse, i.e., both horizontally and vertically. This is simply achieved by particular slits on both ends of the resonator. The prebunching system consists of two cavities. For increasing the longitudinal capture efficiency, the first cavity will be operated at the fundamental accelerator frequency of the S-DALINAC of 3 GHz, and the second cavity at 6 GHz. The cavities are designed to work at the TM010 mode and TM020 mode for the fundamental and first harmonic, respectively.

WEPCH116	Recent Simulation Results of the Polarized Electron Injector (SPIN) of the S-DALINAC	electron, gun, quadrupole, MAMI	2188
	B. Steiner, W.F.O. Müller, T. Weiland TEMF, Darmstadt J. Enders, H.-D. Gräf, C. Heßler, G. Iancu, A. Richter, M. Roth TU Darmstadt, Darmstadt
	Recent design and development for a polarized electron source (SPIN) for the recirculating superconducting electron linear accelerator S-DALINAC will be presented. The polarized electron beam will be produced by photoemission from an InAlGaAs/GaAs superlattice cathode and will be accelerated to 100 kV electrostatically. The results of the beam dynamics simulation will be shown in detail. The start phase space of the electron bunch behind the gun has been approximated. The transverse focusing system consists of very short quadrupoles. Further main components of the new injector are a Wien filter, a Mott polarimeter, a chopper-prebuncher system (based on devices used at the Mainz Mikrotron MAMI), and diverse beam diagnostic tools. For the approximation of the start phase space CST MAFIA is used, and for the beam dynamic simulation VCode is used.

WEPCH117	Beam Dynamics of an Integrated RFQ-drifttube-combination	rfq, ion, GSI, ion-source	2191
	A. Bechtold, M. Otto, A. Schempp IAP, Frankfurt-am-Main
	In the frame of a collaboration with the GSI in Darmstadt an RFQ-Drifttube-Combination for the Heidelberg cancer therapy center HICAT has been designed, built and successfully beam tested at the IAP Frankfurt. The integration and combination of both an RFQ and a rebunching drifttube unit inside a common cavity forming one single resonant RF-structure has been realized for the first time with this machine. The results of the beam measurements and questions about the beam dynamics simulations of such a combination have been investigated in detail with the code RFQSIM.

WEPCH118	LORASR Code Development	linac, rfq, space-charge, proton	2194
	R. Tiede, G. Clemente, H. Podlech, U. Ratzinger, A.C. Sauer IAP, Frankfurt-am-Main S. Minaev ITEP, Moscow
	LORASR is specialized on the beam dynamics design of Separate Function DTL's based on the 'Combined 0 Degree Structure (KONUS)' beam dynamics concept. The code has been used for the beam dynamics design of several linacs already in operation (GSI-HLI, GSI-HSI, CERN Linac 3, TRIUMF ISAC-I) or scheduled for the near future (Heidelberg Therapy Injector, GSI Proton Linac). Recent code development was focused on the implementation of a new PIC 3D FFT space charge routine, facilitating time-efficient simulations with up to 1 million macro particles routinely, as well as of tools for error study and loss profile investigations. The LORASR code was successfully validated within the European HIPPI Project activities: It is the Poisson solver benchmarking and the GSI UNILAC Alvarez section tracking comparison programme. The error study tools are a stringent necessity for the design of future high intensity linacs. The new LORASR release will have a strong impact on the design of the GSI FAIR Facility Proton Linac, as well as the transmission investigations on the IFMIF Accelerator. This paper presents the status of the LORASR code development and the benchmarking results.

WEPCH120	Simulation of 3D Space-charge Fields of Bunches in a Beam Pipe of Elliptical Shape	space-charge, ASTRA, DESY, damping	2200
	A. Markovik, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock K. Floettmann DESY, Hamburg
	Recent applications in accelerator design require precise 3D calculations of space-charge fields of bunches of charged particles additionally taking into account the shape of the beam pipe. An actual problem of this kind is the simulation of e-clouds in damping rings. In this paper a simulation tool for 3D space-charge fields is presented where a beam pipe with an arbitrary elliptical shape is assumed. The discretization of the Poisson equation by the method of finite differences on a Cartesian grid is performed having the space charge field solved only in the points inside the elliptical cross-section of the beam pipe taking care of the conducting boundaries of the pipe. The new routine will be implemented in the tracking code ASTRA. Numerical examples demonstrate the performance of the solution strategy underling the new routine. Further tracking results with the new method are compared to established space-charge algorithms such as the FFT-approach.

WEPCH121	3D Space-charge Calculations for Bunches in the Tracking Code ASTRA	space-charge, ASTRA, DESY, electron	2203
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock K. Floettmann DESY, Hamburg
	Precise and fast 3D space-charge calculations for bunches of charged particles are of growing importance in recent accelerator designs. One of the possible approaches is the particle-mesh method computing the potential of the bunch in the rest frame by means of Poisson's equation. In that, the charge of the particles are distributed on a mesh. Fast methods for solving Poisson's equation are the direct solution applying Fast Fourier Methods (FFT) and a finite difference discretization combined with a multigrid method for solving the resulting linear system of equations. Both approaches have been implemented in the tracking code ASTRA. In this paper the properties of these two algorithms are discussed. Numerical examples will demonstrate the advantages and disadvantages of each method, respectively.

WEPCH122	2D Wake Field Calculations of Tapered Structures with Different FDTD Discretization Schemes	vacuum, LEFT, impedance	2206
	C. Schmidt Rostock University, Institute for General Electrical Engn., Rostock H.-W. Glock, U. van Rienen Rostock University, Faculty of Engineering, Rostock
	The continual performance improvement of particle accelerators requires advanced prediction of parasitic wake field effects, even in structures of comparatively weak influence like tapers. In the case of smooth tapered components, even well established codes like MAFIA* demonstrate strong discretization dependency of the results or solver instabilities, making them not reliable in such applications. Grid dispersion is assumed to generate this failure. In Ref.** an alternative discretization scheme is described, using a homogeneous rotated mesh intended to eliminate such grid dispersion effects. In order to study the dependence on the discretization applied, we use this scheme to calculate wake fields in prototype taper structures of rotational symmetry. Furthermore a comparison is provided with the results of a non-rotated mesh, MAFIA runs and - so far applicable - analytical approaches. MAFIA V4.107: CST GmbH, Bad Nauheimer Str. 19, D-64289 Darmstadt*R. Hampel et al. New discretization scheme for wake field computation in cylindrically symmetric structure. Proc. EPAC'04, pp 2559

WEPCH123	Large Simulation of High Order Short Range Wakefields	higher-order-mode, dipole, SLAC, DESY	2209
	A. Bungau Cockcroft Institute, Warrington, Cheshire R.J. Barlow UMAN, Manchester
	We present a formalism for incorporating intra-bunch wake fields into particle-by-particle tracking codes, such as MERLIN and BDSIM. Higher order wake field effects are incorporated in a manner which is computationally efficient. Standard formulae for geometric, resistive and dielectric wake fields are included for various apertures, particularly those relevant for ILC collimators. Numerous examples are given.

WEPCH124	BDSIM - Beamline Simulation Toolkit Based on Geant4	quadrupole, electron, CLIC, scattering	2212
	I.V. Agapov, G.A. Blair, J. Carter Royal Holloway, University of London, Surrey O. Dadoun LAL, Orsay
	BDSIM is a code that combines accelerator-style particle tracking with traditional Geant-style tracking based on Runge-Kutta techniques. This approach means that particle beams can be tracked efficiently when inside the beampipe, while also enabling full Geant4 processes when beam-particles interact with beamline apertures. Tracking of the resulting secondary particles is automatic. The code is described, including a new MAD-style interface and new geometry description, and key performance parameters are listed.

WEPCH125	New Design Tools for a Cyclotron Central Region	cyclotron, emittance, ion, injection	2215
	D. Battaglia, L. Calabretta, D. Campo, M.M. Maggiore, L.A.C. Piazza, D. Rifuggiato INFN/LNS, Catania
	A code that allows us to design the spiral inflector and the central region of the SCENT cyclotron was implemented. The code integrates the main equations of motion of a particle in an electromagnetic field and provides an useful interface to describe the geometry and the physical constraints of the inflector and the central region to be simulated. The mechanical drawings of the inflector and the central region is made using a standard CAD. These drawings are then imported in OPERA 3D to produce the maps of the electric and magnetic field. An application interface allows us to enter the emittance and the particles’ distributions to be transported through the inflector. An iterative process to design the central region was also developed and tested.

WEPCH128	Virtual Accelerator as an Operation Tool at J-PARC 3 GeV Rapid Cycling Synchrotron (RCS)	betatron, synchrotron, optics, feedback	2224
	H. Harada, K. Shigaki Hiroshima University, Higashi-Hiroshima K. Furukawa KEK, Ibaraki H. Hotchi, F. Noda, H. Sako, H. Suzuki JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	We developed a virtual accelerator based on EPICS for 3 GeV Rapid-Cycle Synchrotron (RCS) in J-PARC. It is important to have an on-line model of optics parameters, such as tunes, Twiss parameters, dispersion function, at the commissioning stage in a high intensity proton machine. It gives a strong feedback for the RCS operation as a commissioning tool as well as for the studies of beam dynamics issues. Beam position monitors with finite resolutions, a transverse exciter to measure the betatron frequency, and a RF system with variable frequency to simulate off-momentum optics have been implemented into the system. The virtual accelerator system itself and some results of beam dynamics studies will be presented.

WEPCH131	Development of Numerical Code for Self-consistent Wake Field Analysis with Curved Trajectory Electron Bunches	electron, electromagnetic-fields, radiation, coupling	2230
	H. Kawaguchi Muroran Institute of Technology, Department of Electrical and Electronic Engineering, Muroran K. Fujita Hokkaido University, Sapporo
	Strongly interacting phenomena of electromagnetic radiation fields and ultra-relativistic electron is one of great interests in accelerator science such as in electron beam dynamics at the bunch compressor. The phenomena are described by time domain boundary value problem for the Lienard-Wiechert solutions. Authors develop a time domain boundary element method for self-consistent wake fields analysis of electromagnetic fields and charged particles. To use boundary integral equation for describing the electromagnetic fields, the time domain boundary value problems for the Lienard-Wiechert solution can be naturally formulated and we can simulate the wake fields phenomena with electron beam dynamics. In this paper, beam dynamics of curved trajectory electron bunches inside uniform beam tube are numerically simulated by using 2.5 dimension time domain boundary element technique. Various effects of closed beam tube for ultra-relativistic electron dynamics are considered comparing with the Lienard-Wiechert solutions in free space.

WEPCH132	Design Study of Dedicated Computer System for Wake Field Analysis with Time Domain Boundary Element Method	BNL, CSR, electron, controls	2233
	K. Fujita, T. Enoto Hokkaido University, Sapporo H. Kawaguchi Muroran Institute of Technology, Department of Electrical and Electronic Engineering, Muroran
	Time domain boundary element method (TDBEM) has advantages of dispersion free calculations and modeling of curved beam trajectories in wake field analysis compared to conventional methods. These advantages give us powerful possibilities for analysis of beam dynamics due to CSR in bunch compressors of next-generation accelerators. On the other hand, the TDBEM also has a serious difficulty of large computational costs. In this paper, a dedicated computer system for wake field analysis with the TDBEM is proposed as one of solutions for high performance computing (HPC) technologies. Recent remarkable progress of LSI hardware design environments such as HDL compiler tools and large scale FPGAs enables us to make up computer hardware systems with very low cost in a short development period. The authors have been working in design studies of the TDBEM dedicated computer system on such LSI design environments. This paper presents a system design and VHDL simulations of a wake field analysis machine based on the TDBEM.

WEPCH134	Development of Code for Simulation of Acceleration of Ions from Internal Source to End of Extraction System in Cyclotrons and Preliminary Design Study of 8MeV Cyclotron for Production of Radioisotopes	cyclotron, extraction, acceleration, ion	2236
	S.A. Kostromin JINR, Dubna, Moscow Region
	From the users' point of view modern cyclotrons must be compact, energy-saving, low-radiation and very reliable facilities. To provide all these characteristics, a very detailed design study of all systems of an accelerator under development is required. Thus, particle tracking from the "beginning" to the "end" in modern cyclotrons with small gaps in the main acceleration region and with efficient extraction systems becomes a very important task for designers. Codes for beam dynamics simulation at the center, main acceleration region and through the extraction system of the cyclotron have been developed. It is possible to monitor all main beam parameters at the different stages of acceleration, radial, axial and phase motion of the beam and the energy increase. During tracking particles through the extraction system it is possible to calculate rms envelopes of radial and vertical motion of the beam and beam losses at the aperture of the extraction system elements. A preliminary design of a compact 8-MeV proton cyclotron was studied using created codes. The accelerator is supposed to have a four sector compact magnet system with the pole 64 cm in diameter.

WEPCH136	Monte Carlo Simulation Model of Internal Pellet Targets	target, scattering, injection, storage-ring	2239
	O.A. Bezshyyko, K.A. Bezshyyko, I.M. Kadenko, R.V. Yermolenko National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv A. Dolinskii NASU/INR, Kiev V.G. Ziemann UU/ISV, Uppsala
	We develop a numerical model of a pellet target and use it for Monte Carlo simulations of the interaction of a circulating beam with a pellet target. Real geometry details of the pellet beam and the beam are taken into account. We emphasize the role of tails of non-Gaussian distributions for transverse scattering and energy loss. These effects are especially important for simultaneous calculations of electron cooling, intrabeam scattering and target influence. Black-box algorithms for the generation of automatic nonuniform random variate distributions are used for the effective time averaging of scattering angle and energy loss distributions.

WEPCH137	FAKTOR2: A Code to Simulate the Collective Effects of Electrons and Ions	electron, ion, LEFT, CLIC	2242
	W. Bruns, D. Schulte, F. Zimmermann CERN, Geneva
	A new code for computing the multiple effects of slowly moving charges is being developed. The basic method is electrostatic particle in cell. The underlying grid is rectangular and locally homogeneous. At regions of interest, e.g., where the beam is, or near material boundaries, the mesh is refined recursively. The motion of the macroparticles is integrated with an adapted timestep. Fast particles are treated with a smaller timestep, and particles in regions of fine grids are also treated with a fine timestep. The position of collision of particles with material boundaries is accurately resolved. Secondary particles are then created according to user-specified yield functions.

WEPCH138	Simulations of Long-range Beam-beam Interaction and Wire Compensation with BBTRACK	LHC, RHIC, luminosity, emittance	2245
	U. Dorda, F. Zimmermann CERN, Geneva
	We present weak-strong simulation results for the effect of long-range beam-beam collisions in LHC, SPS, RHIC and DAFNE, as well as for proposed wire compensation schemes or wire experiments, respectively. In particular, we discuss details of the simulation model, instability indicators, the effectiveness of compensation, the difference between nominal and PACMAN bunches for the LHC, beam experiments, and wire tolerances. The simulations are performed with the new code BBTRACK.

WEPCH139	WISE: An Adaptative Simulation of the LHC Optics	LHC, CERN, quadrupole, power-supply	2248
	P. Hagen, M. Giovannozzi, J.-P. Koutchouk, T. Risselada, S. Sanfilippo, E. Todesco, E.Y. Wildner CERN, Geneva
	The LHC beam dynamics requires a tight control of the magnet field quality and geometry. As the production of the magnets advances, decisions have to be made on the acceptance of possible imperfections. To ease decision making, an adaptative model of the LHC optics has been built, based on the current information available (e.g. magnetic measurements at warm or cold, magnet allocation to machine slots) as well as on statistical evaluations for the missing information (e.g. magnets yet to be built, measured, or for non-allocated slots). The uncertainties are included: relative and absolute measurement errors, warm-to-cold correlations for the fraction of magnets not measured at cold, hysteresis and power supply accuracy. A pre-processor generates instances of the LHC ring for the MADX program, with the possibility of selecting various error sources. A post-processor computes ranges for relevant beam optics parameters and distributions. This approach has been applied to the expected beta-beating, to the possible impact of permeability issues in some quadrupole collars, to the geometrical displacements of the multipolar correctors and to prioritize the magnetic measurement programme.

WEPCH140	Recent Improvements of PLACET	CLIC, linac, ground-motion, luminosity	2251
	A. Latina, H. Burkhardt, L. Neukermans, G. Rumolo, D. Schulte, R. Tomas CERN, Geneva P. Eliasson Uppsala University, Uppsala J. Resta-López IFIC, Valencia
	The tracking code PLACET is used to simulate the beam transport in linear colliders from the damping ring to the interaction point and beyond. Recent improvements of the code are presented. They include the possibility to simulate bunch compressors and to use parallel computer systems.

WEPCH141	Accelerator Physics Code Web Repository	electron, CERN, space-charge, site	2254
	F. Zimmermann, R. Basset, E. Benedetto, U. Dorda, M. Giovannozzi, Y. Papaphilippou, T. Pieloni, F. Ruggiero, G. Rumolo, F. Schmidt, E. Todesco CERN, Geneva D.T. Abell Tech-X, Boulder, Colorado R. Bartolini Diamond, Oxfordshire O. Boine-Frankenheim, G. Franchetti, I. Hofmann GSI, Darmstadt Y. Cai, M.T.F. Pivi SLAC, Menlo Park, California Y.H. Chin, K. Ohmi, K. Oide KEK, Ibaraki S.M. Cousineau, V.V. Danilov, J.A. Holmes, A.P. Shishlo ORNL, Oak Ridge, Tennessee L. Farvacque ESRF, Grenoble A. Friedman LLNL, Livermore, California M.A. Furman, D.P. Grote, J. Qiang, G.L. Sabbi, P.A. Seidl, J.-L. Vay LBNL, Berkeley, California D. Kaltchev TRIUMF, Vancouver T.C. Katsouleas USC, Los Angeles, California E.-S. Kim PAL, Pohang, Kyungbuk S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon J. Payet CEA, Gif-sur-Yvette T. Sen Fermilab, Batavia, Illinois J. Wei BNL, Upton, Long Island, New York B. Zotter Honorary CERN Staff Member, Grand-Saconnex
	In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans.

WEPCH143	Electron Linac Based e,X-radiation Facility	target, electron, radiation, photon	2257
	V.I. Nikiforov, A. Dovbnya, N.A. Dovbnya, V.L. Uvarov NSC/KIPT, Kharkov
	In a number of technologies based on high-current electron accelerators bremsstrahlung is generated in the interaction of the beam with the irradiated object. Thus, in addition to the electron radiation, the bremsstahlung may be used for carring out of different technolodgical programs (e,X-facility). A method for the numerical analysis and optimization of the radiation characteristics of such installation is proposed. The accelerator beam track, starting from the electron source and up to output devices is considered as a single multicomponent target consisting of the layers of different materials. The thickness of each layer is measured in the generalized units of the "stopping length". Using the method of simulation based on the PENELOPE/2001 system the characteristics of the mixed e,gamma-radiation field (energy yield of electrons, photons and their ratio) as function of the stopping length for actual or anticipated version of output equipment can be calculated. To illustrate the method, the parameters of the beam path of the NSC KIPT Linacs used as e,X-facilities was analyzed.

WEPCH144	CSR Effects in a Bunch Compressor: Influence of the Transverse Force and Shielding	shielding, LEFT, CSR, radiation	2260
	G. Bassi, J.A. Ellison, K.A. Heinemann UNM, Albuquerque, New Mexico
	We study the influence of CSR on particle bunches traveling on arbitrary planar orbits between parallel conducting plates with a fixed "vertical" charge distribution. Our goal is a numerical solution of the 2 degree-of-freedom Vlasov-Maxwell equations. This provides simulations with lower numerical noise than the macroparticle method and allows the study of emittance degradation and microbunching. As reported, we calculate the fields excited by the bunch in the lab frame using a new formula that leads to a simplification. The Vlasov equation is integrated in the beam frame interaction picture using the method of local characteristics. The transformation between traditional beam frame and lab frame coordinates is carefully treated. Here we report on our implementation of the algorithm in the context of a chicane bunch compressor, where the strong correlation between phase space variables requires an adaptive grid. In particular, we present a complete analysis (moments + reduced densities) of the bunch evolution under the fields produced by the unperturbed bunch density. Finally, our progress on the fully self-consistent case is discussed. Vlasov treatment of coherent synchrotron radiation from arbitrary planar orbits, Nucl. Instr. Meth. Phys. Res. A, in press.** ICFA Beam Dynamics Mini-Workshop on CSR, Berlin-Zeuthen, 2002. See http://www.desy.de/csr.

WEPCH145	Particle Tracking and Simulation on the .NET Framework	lattice, KEK, controls, closed-orbit	2263
	H. Nishimura, T. Scarvie LBNL, Berkeley, California
	Particle tracking and simulation studies are becoming complex. In addition to the sophisticated graphics, interactive scripting is becoming popular. A compatibility with the control system requires network and database capabilities. It is not a trivial task to fulfill various requirements without sacrificing the runtime performance. We evaluate the use of .NET to solve this issue by converting a C++ code Goemon* that is an object-oriented version of Tracy developed at ALS. The portability to other platforms will be mentioned in terms of Mono. *H. Nishimura, PAC'01, Chicago, July 2001, p.3066.

WEPCH147	Simulations of Electron Effects in Superconducting Cavities with the VORPAL Code	electron, plasma, laser, radio-frequency	2269
	C. Nieter, J.R. Cary, P. Messmer, D.S. Smithe, P. Stoltz Tech-X, Boulder, Colorado G.R. Werner CIPS, Boulder, Colorado
	Modeling the complex boundaries of superconducting radio frequency (SRF) accelerating cavities on a Cartesian grid is a challenge for many Finite Difference Time Domain (FDTD) electromagnetic PIC codes. The simulation of such cavities require conformal (curve fitting) boundaries. Modeling the full cavity including couplers and ports is fundamentally a three dimensional problem requiring capability to run in parallel on large numbers of processors. We have recently added conformal boundaries using the method of Zagorodnov* to the plasma simulation code VORPAL. Using this higher order boundary algorithm and the surface physics package TxPhysics, we have begun studies of self-consistent electron effects in SRF cavities. We have modeled the beam excitation of cavity modes and the effects of electron multipacting. Results from these studies will be presented using the new user friendly visualization tool that now ships with VORPAL. *I. A. Zagorodnov et al. “A uniformly stable conformal FDTD-method in Cartesian grids,” International Journal of Numerical Modeling 16, 127 (2003).

WEPCH149	PBO LAB (tm) Tools for Comparing MARYLIE/MAD Lie Maps and TRANSPORT/TURTLE Transfer Matrices	optics, quadrupole, beam-transport, controls	2275
	G.H. Gillespie, W. Hill G.H. Gillespie Associates, Inc., Del Mar, California
	Particle optics codes frequently utilize either a Lie algebraic formulation or a matrix formulation of the equations of motion. Examples of codes utilizing the Lie algebra approach include MARYLIE and MAD, whereas TRANSPORT and TURTLE use the matrix formulation. Both types of codes have common application to many particle optics problems. However, it is often a very tedious exercise to compare results from the two types of codes in any great detail. As described in a companion paper in these proceedings, differences in the choice of phase space variables, as well as the inherent differences between the Lie algebraic and matrix formulations, make for unwieldy and complex relations between results from the two types of codes. Computational capabilities have been added to the PBO Lab software that automates the calculation of transfer matrices from Lie maps, and that converts phase space distributions between the different representations used by the codes considered here. Graphical and quantitative comparison tools have been developed for quick and easy visual comparisons of transfer maps and matrices.

WEPCH157	Design and Beam Dynamics Simulation for the Ion-injector of the Austrian Hadron Therapy Accelerator	ion, proton, synchrotron, extraction	2296
	Th. Strodl ATI, Wien
	MedAustron is an initiative for the construction of the Austrian Hadron Therapy Centre. In 2004 the design study was presented. The basic design consists of two ion sources, an ion-injector, a synchrotron and a beam transfer line with five possible beam exits. The synchrotron is based on the proton ion medical machine study (PIMMS) design with some modifications. The injector is based on the GSI design of the Heidelberg ion therapy cancer accelerator with the original radio frequency quadrupole and IH-Linac. Modifications have been done in the design of the low energy beam transport and the medium energy beam transport lines. The impact of these modifications has been investigated, and several other beam scenarios have bean simulated with different simulation codes.

WEPCH162	Magnet Simulations for Medical FFAG	dipole, magnet-design, CERN	2310
	E. Froidefond LPSC, Grenoble B. Autin CERN, Geneva
	Studies have been undertaken concerning magnet design in the frame of the RACCAM FFAG project (this conference). This contribution reports on the objectives of the project in that matter, on the working methods and calculation tools developments, magnetic field modeling and simulations, and on the present status of this work.

WEPCH167	Study of Scatterer Method to Compensate Asymmetric Distribution of Slowly Extracted Beam at HIMAC Synchrotron	scattering, extraction, emittance, synchrotron	2322
	T. Furukawa, K. Noda, S. Sato, S. Shibuya, E. Takada, M. Torikoshi, S. Yamada NIRS, Chiba-shi
	In the medical use of the ion beam, the following characteristics of the beam are preferred: 1) Symmetric Gaussian beam profile is convenient for the scanning irradiation. 2) In the rotating gantry system, the symmetric beam condition can realize no-correlation between the beam profiles and the rotation angles of the gantry. However, the slowly extracted beam has asymmetric distribution in the phase-space and a difference between the horizontal emittance and vertical one. Thus, we have proposed the thin scatterer method to compensate the phase-space distribution of the slowly extracted beam, although the emittance is enlarged by scattering. As a result of particle tracking and experiment, it was verified that the asymmetric distribution was compensated by very small scattering angle. It was also simulated that this scatterer method can realize the symmetric beam condition for the rotating gantry. In this paper, these results of asymmetry compensation for the slow-extraction at HIMAC is presented.

WEPCH173	The Performance of Double-grid O-18 Water Target for FDG Production	target, cyclotron, proton, radiation	2337
	H.B. Hong, J.-S. Chai, M.G. Hur, H.S. Jang, J. Kang KIRAMS, Seoul H.H. Cho, K.M. Kim Yonsei University, Seoul
	The main stream of our study about the target is increasing the lifetime of the target windows. Mainly we conduct our study to increase the cooling performance and secondly about the structural design of the targets and target window foils. We already had developed and had published the results of our research about O-18 double-grid water target, which had installed on our 13 MeV cyclotron KIRAMS-13. The beam size of the accelerated proton was 9 mm18 mm (0.35 in 0.7 in). The double-grid target shows relatively low pressure during irradiation and good yield of F-18. The average yield of F-18 after irradiation was more than 1 Ci at 12.5 MeV , around 26 μA. Additionally, we are conducting new research for new techniques to increase the performance of low energy double-grid target and a new state-of-the-art pleated double foil target.

WEPCH177	Conception of Medical Isotope Production at Electron Accelerator	target, electron, radiation, isotope-production	2343
	V.L. Uvarov, N.P. Dikiy, A. Dovbnya, V.I. Nikiforov NSC/KIPT, Kharkov
	A photonuclear method with the use of high-energy bremsstrahlung (Eg>8 MeV) of high intensity (>= 10⁰⁴ W/cm2) provides a possibility of the ecologically safe production of a number of isotopes for nuclear medicine. The conditions of generation of the radiation field having such characteristics as well as the features of photonuclear production of W-181,Pd-103, Cu-67 and other radionuclides are considered in the report. At the initial stage the study of the isotope production is performed by means of the computer simulation in a simplified 2D geometry of the Linac output devices. The code on the base of the PENELOPE/2001 program system supplemented with the data on the excitation functions of the corresponding reactions was developed. The dependences of the isotope yield (gross and specific activity) on the electron energy (30…45 MeV), as well as, the data on absorbed energy of radiation in the targets of natural composition are represented. The experimental results confirm the data of modelling. Main trends of realization of the photonuclear method for isotope production and the necessary conditions of the increase of its yield are analysed.

WEPCH178	Simulation Study of Compact Hard X-ray Source via Laser Compton Scattering	electron, linac, focusing, laser	2346
	R. Kuroda, M.K. Koike, H. Ogawa, N. Sei, H. Toyokawa, K. Y. Yamada, M.Y. Yasumoto AIST, Tsukuba, Ibaraki N. Nakajyo, F. Sakai, T. Yanagida SHI, Tokyo
	The compact hard X-ray source via laser Compton scattering between high intensity electron beam and high power laser beam was developed at FESTA (The Femtosecond Technology Research Association) project in collaboration between AIST and SHI. According to completion of the project in March 2005, the compact hard X-ray source is being transferred from FESTA to AIST to upgrade and to apply the system to biological and medical uses. Our system consists of a laser-driven photocathode rf gun, two 1.5m-long S-band accelerator structures and a high power Ti:Sa Laser system. This system can generate a hard X-ray pulse which has variable energy of 12 keV – 33 keV with narrow bandwidth by changing electron energy and collision angle. Maximum X-ray photon yield at FESTA was accomplished about 10⁷photons/s (@10Hz, MAX 33keV) in case of 165 degree collision angle. In the next phase, we are planning to make the total system much compact using X-band or C-band accelerator structures with permanent magnets. We have carried out the numerical simulations to investigate the possibility of these compact systems. In this conference, we will talk about results of the simulations and future plans.

WEPCH187	A Compact 5 MeV, S-band, Electron Linac Based X-ray Tomography System	linac, electron, radiation, collimation	2370
	L. Auditore, L. Auditore, R.C. Barnà, D. De Pasquale, D. Loria, A. Trifirò, M. Trimarchi INFN & Messina University, S. Agata, Messina U. Emanuele, A. Italiano INFN - Gruppo Messina, S. Agata, Messina
	The availability of commercial X-ray tubes made of radiography and tomography two of the most used non-destructive testing techniques both in industrial and cultural heritage fields. Nevertheless, the inspection of heavy materials or thick objects requires X-ray energies larger than the maximum energy provided by commercial X-ray tubes (600 kV). For this reason, and owing to the long experience of the INFN-Gruppo Collegato di Messina in designing and assembling low energy electron linacs, at the Dipartimento di Fisica, Universita di Messina, a 5 MeV electron linac based X-ray tomographic system has been developed. The X-ray source, properly designed by means of the MCNP-4C2 code, provides a 16 cm diameter X-ray spot at the sample position and a beam opening angle of about 3.6 degree. The image acquisition system consists of a CCD camera (Alta Apogee E1, 768x512 pixel) and a GOS scintillating screen. Preliminary radiographies and tomographies showing the high quality performances of the tomographic system have been acquired. Finally, the compactness of the linac, is one of the advantages of this system that could be used for in situ inspections when huge structures have to be tested

WEPCH190	A Ridge Filter for 36 MeV Proton Beam Applied to BT and ST	proton, ion, target, radioactivity	2379
	Y.K. Lim, K. R. Kim KAERI, Daejon
	We designed a ridge filter to obtain a uniform depth-dose distribution as well as to deliver high linear energy transfer along the depth of a target for 36MeV proton beam. Aluminum was chosen as the material of the filter to reduce the radioactivity induced by proton irradiation. The designed ridge filter has a continuous cross-sectional line shape of ridges so that the smoothly varying depth-dose distribution can be maintained before the distal fall-off for lower proton energy than 36MeV. The height of the ridge is 6 mm, its period is also 6 mm and the minimum thickness is 0.3 mm. A Monte Carlo simulation code, MCNPX 2.5.0., was used to calculate the dose distributions. The width of the calculated uniform dose region was 11 mm for 36MeV proton beam in a water-equivalent sample.

WEPLS001	Secondary Particle Production and Capture for Muon Accelerator Applications	target, proton, lattice, factory	2394
	S.J. Brooks CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	Intense pulsed muon beams are required for projects such as the Neutrino Factory and Muon Collider. It is currently proposed to produce these from a high-Z target using a multi-megawatt proton driver. This paper examines the effect of proton energy on the yield and distribution of particles produced from tantalum and mercury, with further analysis using a tracking code to determine how these distributions will behave downstream, including a breakdown of loss mechanisms. Example 'muon front end' lattices are used from the UK Neutrino Factory design.

WEPLS002	Design and Expected Performance of the Muon Beamline for the Muon Ionisation Cooling Experiment	target, emittance, proton, extraction	2397
	K. Tilley, D.J. Adams, P. Drumm CCLRC/RAL/ISIS, Chilton, Didcot, Oxon T.J. Roberts Muons, Inc, Batavia K.a. Walaron University of Glasgow, Glasgow
	It is proposed to install a Muon Ionisation Cooling Experiment (MICE) at the ISIS facility, at Rutherford Appleton Laboratory (RAL). This experiment will be the first demonstration of ionisation cooling as a means to reduce the large transverse emittance of the muon beam, produced during the early stages of a Neutrino Factory. In order to permit a realistic demonstration of cooling, a beam of muons must be produced, possessing particular qualities, notably in emittance and momenta. This paper describes the current design for the muon beamline, outlining issues particular to the needs of the MICE experiment, and discusses its expected performance.

WEPLS003	Simulation of MICE Using G4MICE	emittance, factory, quadrupole, coupling	2400
	C.T. Rogers Imperial College of Science and Technology, Department of Physics, London R. Sandstrom DPNC, Genève
	In the Muon Ionisation Cooling Experiment (MICE), muons will be fired one by one through one or two cooling cells. The experiment will be used to optimise simulation of an ionisation cooling channel for a future Neutrino Factory. This is achieved by measuring the position of each muon in six-dimensional phase space and examining the behaviour of muons collected into bunches offline. The experiment will be run with a number of different input beams, magnet configurations, RF configurations and absorber types. We present the simulated detector and cooling performance of the MICE cooling channel using the G4MICE simulation code for a range of configurations. We detail the simulation of engineering, field and detector models and examine the implications for the cooling efficacy and measurement.

WEPLS007	A Six-dimensional Muon Beam Cooling Experiment	emittance, dipole, collider, beam-cooling	2409
	R.P. Johnson, M. Alsharo'a, M.A.C. Cummings, M. Kuchnir, K. Paul, T.J. Roberts Muons, Inc, Batavia D.M. Kaplan Illinois Institute of Technology, Chicago, Illinois V.S. Kashikhin, V. Yarba, K. Yonehara Fermilab, Batavia, Illinois
	Ionization cooling, a method for shrinking the size of a particle beam, is an essential technique for the use of muons in future particle accelerators. Muon colliders and neutrino factories, examples of such future accelerators, depend on the development of robust and affordable ionization cooling technologies. A 6D cooling experiment has been proposed, incorporating a novel configuration of helical and solenoidal magnets in a prototype cooling channel. This Helical Cooling Channel (HCC) experiment is being designed with simulations and prototypes to provide an affordable and striking demonstration that 6D muon beam cooling is understood well enough to enable intense neutrino factories and high-luminosity muon colliders. Because of the large amount of expected beam cooling, helium instead of hydrogen can be used for the initial experiment, avoiding the safety complications of hydrogen. Cryostats are currently being developed using internal heat exchangers for simple, effective and safe hydrogen absorber systems to use in later cooling experiments and real cooling channels. The experimental design choices and corresponding numerical simulations are reviewed.

WEPLS016	Studies of a Gas-filled Helical Muon Beam Cooling Channel	emittance, dipole, sextupole, quadrupole	2424
	R.P. Johnson, K. Paul, T.J. Roberts Muons, Inc, Batavia Y.S. Derbenev Jefferson Lab, Newport News, Virginia K. Yonehara Fermilab, Batavia, Illinois
	A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. We consider liquid helium and liquid hydrogen absorbers in HCC segments that alternate with RF accelerating sections and we also consider gaseous hydrogen absorber in pressurized RF cavities imbedded in HCC segments. In the case of liquid absorber, the possibility of using superconducting RF in low magnetic field regions between the HCC segments may provide a cost effective solution to the high repetition rate needed for an intense neutrino factory or high average luminosity muon collider. In the gaseous hydrogen absorber case, the pressurized RF cavities can be operated at low temperature to improve their efficiency for higher repetition rates. Numerical simulations are used to optimize and compare the liquid and gaseous HCC techniques.

WEPLS039	Developments on a Diamond-based Cylindrical Dielectric Accelerating Structure	DIAMOND, impedance, electron, vacuum	2460
	A. Kanareykin, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio M.E. Conde, W. Gai, J.G. Power ANL, Argonne, Illinois P. Schoessow Tech-X, Boulder, Colorado
	Developments on a high gradient diamond-based cylindrical dielectric loaded accelerator (DLA) is presented. A diamond-loaded DLA can potentially sustain accelerating gradients far in excess of the limits experimentally observed for conventional metallic accelerating structures. The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerators: high RF breakdown level, extremely low dielectric losses and the highest available thermoconductive coefficient. We used the hot-filament Chemical Vapor Deposition (CVD) process to produce high quality 5-10 cm long cylindrical diamond layers. Our collaboration has also been developing a new method of CVD diamond surface preparation that reduces the secondary electron emission coefficient below unity. Special attention was paid to the numerical optimization of the coupling section, where the surface magnetic and electric fields were minimized relative to the accelerating gradient and within known metal surface breakdown limits.

WEPLS042	Design and Experimental Investigation of an X-band Multilayer Dielectric Accelerating Structure	impedance, vacuum, coupling, DESY	2466
	A. Kanareykin, C.-J. Jing, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio W. Gai, J.G. Power ANL, Argonne, Illinois
	A new project to significantly improve the efficiency of high gradient DLA structures is presented. A multilayer DLA where the single dielectric layer is replaced by a multiple coaxial layers of differing permittivity have been developed. The power attenuation in the multilayer structure is reduced by the Bragg Fiber principle where the dielectric layers are used to create multiple reflections in order to confine the accelerating mode fields for the most part in the dielectric, reducing the axial current on the conducting outer boundary. A design for an X-band multilayer structure operating in the TM03 mode using alternating dielectric layers with permittivities of 38 and 9.7 is discussed. In order to transfer the RF from the rectangular waveguide to the cylindrical one at TM03 mode, a special coupling and mode conversion scheme was developed. A prototype structure has been constructed and bench test results of the multilayer 11.424 GHz accelerator is presented.

WEPLS047	3-1/2 Cell Superconducting RF Gun Simulations	gun, cathode, emittance, focusing	2481
	C.D. Beard, J.H.P. Rogers CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire F. Staufenbiel, J. Teichert FZR, Dresden
	A 3-1/2 cell superconducting RF photocathode gun is being developed at Forschungszentrum Rossendorf to produce a high peak current, low emittance electron beam. This technology is essential to the realisation of many large scale facilities. The gun is designed for CW operation mode with 1 mA current and 9.5 MeV electron energy, and it will be installed at the ELBE superconducting electron linear accelerator. The gun will have a 3-1/2 cell niobium cavity operating at 1.3 GHz. The cavity consists of three cells with TESLA geometry and a specially designed half-cell in which the photocathode will be placed. Typical ERL-based projects require ~100 mA average current, and therefore suitable upgrade paths are required. Simulations have been carried out to evaluate the design and to determine suitable upgrades for higher current operation. Simulations of alternative cathode surface shapes are presented. Several couplers have been identified that can provide higher power to the cavity, whose integration and suitability has been verified. All the investigations that have identified possible solutions to higher current operation are discussed in this report.

WEPLS049	The Design of a Hybrid Photoinjector for High Brightness Beam Applications	gun, coupling, emittance, bunching	2487
	D. Alesini, M. Ferrario, V. Fusco, B. Spataro INFN/LNF, Frascati (Roma) L. Ficcadenti, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma B. O'Shea, J.B. Rosenzweig, G. Travish UCLA, Los Angeles, California
	In this paper, we illustrate the electromagnetic and beam dynamics design procedure of a new class of photoinjector, a hybrid standing/traveling wave structure. In this device a standing wave RF gun section is integrated with a downstream traveling wave structure through a coupling cell that feeds simultaneously the two sections. We discuss the advantages in RF and beam performance of the hybrid photoinjector compared to conventional systems. The electromagnetic design has been performed using the 2D and 3D electromagnetic codes Superfish and HFSS. Results of beam dynamics simulations in different operating conditions are also discussed.

WEPLS053	RF Design of a Cartridge-type Photocathode RF Gun in S-band Linac	linac, cathode, gun, vacuum	2499
	H. Moritani, Y. Muroya, A. Sakumi, T. Ueda, M. Uesaka UTNL, Ibaraki H. Hanaki, N. Kumagai, S. Suzuki, H. Tomizawa JASRI/SPring-8, Hyogo-ken J. Sasabe Hamamatsu Photonics K.K., Hamakita, Shizuoka J. Urakawa KEK, Ibaraki
	A cartridge-type photocathode RF gun is under development in collaboration with SPring-8 and Hamamatsu Photonics. Each type of cathode (Cs2Te, Mg, diamond, Ag-Cs-O) is sealed in a cartridge-type vacuum tube. Several tubes can be installed in a vacuum chamber. The cathode in the tube is inserted into a center hole in the back plate of the RF gun by a vacuum manipulator. These cartridge-type photocathodes with high QE or sensitivity for visible lights, which are prepared in a factory, can be used for a long time without vacuum breaking. Since a load-lock system for forming a new high QE film is not needed, the cartridge-type RF gun becomes compact. We are going to introduce this cartridge-type system to our linac with the BNL-GUN-IV RF gun this summer. Now, we are calculating the gun parameters of the transmission cavity which has a back plate with a center hole 8mm in diameter with SUPERFISH and simulating the beam dynamics after modifying the beam line to install the system with PARMELA. We aim to use reliable Mg and high-QE Cs2Te and try diamond and Ag-Cs-O for radiation chemistry applications. The detailed numerical design and construction will be presented.

WEPLS054	Higher-order Effect Compensation in Magnetic Compressor for < 50 fs Electron Bunch Generation	electron, linac, gun, quadrupole	2502
	K. Kan, T. Kondoh, J. Yang, Y. Yoshida ISIR, Osaka
	An ultrashort electron bunch is essential for pulse radiolysis, which is a pump-probe measurement based on an ultrashort electron beam and an ultrashort light. In Osaka University, a laser photocathode electron linear accelerator with a magnetic compressor has been constructed for the femtosecond electron bunch generation. An electron beam with bunch length of 98 fs was successfully generated and used in pulse radiolysis. However, an electron beam with bunch length of < 50 fs is required for development of pulse radiolysis with time resolution of 100 fs. To generate such a short bunch, higher order disadvantage effects, which are caused by the fringing fields of the magnets in the compressor, should be compensated. In this paper, a compensation technique of higher-order effects was proposed by using a nonlinear energy modulation in the bunch produced in the linear accelerator by re-phasing the linac away from the zero-crossing of the rf (i.e., away from the linear slope). In the simulation, we compressed the electron bunch into 48 fs at bunch charge of 0.1 nC.

WEPLS056	R&D Status of the High-intense Monochromatic Low-energy Muon Source: PRISM	impedance, lepton, synchrotron, focusing	2508
	A. Sato, M. Aoki, Y. Arimoto, I. Itahashi, Y. Kuno, K. Kuriyama, T. Oki, T. Takayanagi, M. Yoshida Osaka University, Osaka M. Aiba, C. Ohmori, T. Yokoi, K. Yoshimura KEK, Ibaraki Y. Iwashita Kyoto ICR, Uji, Kyoto S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon Y. Mori KURRI, Osaka
	PRISM is a project of a future intense low-energy muon source, which combines monochromaticity and high purity. Its aimed intensity is about $10¹¹-10¹² muons per second. The muon beams will have a low kinetic energy of 20MeV so that it would be optimized for the stopped muon experiments such as searching the muon lepton flavor violating processes. PRISM consists of a pion capture section, a pion/muon transfer section and a phase rotation ssection. An FFAG is used as the phase rotator to achieve the monochromatic muon beams. This paper will describe design status of these sections as well as construction status of PRISM-FFAG.

WEPLS092	Computer Modeling of Magnetic System for C400 Superconducting Cyclotron	cyclotron, extraction, injection, focusing	2589
	Y. Jongen, D. Vandeplassche, S.E. Zaremba IBA, Louvain-la-Neuve G.A. Karamysheva, N.A. Morozov, E. Samsonov JINR, Dubna, Moscow Region
	The superconducting cyclotron (C400) is designed at IBA (Belgium) able to accelerate carbon ions at 400 MeV/nucleon. By computer simulation with 3D TOSCA code, the cyclotron magnetic system principal parameters were estimated (pole radius 187 cm, outer diameter 606 cm, valley depth 60 cm, height 276 cm). The required isochronous magnetic field was shaped with an accuracy of ± 2 mT. Four-fold symmetry and spiralized sectors with elliptical gap (minimal 12 mm at extraction) provide the stable beam acceleration till 15 mm from the pole edge.

WEPLS094	3D Magnetic Field and Eddy Current Loss Calculations for Iron Dominated Accelerator Magnets using ANSYS Compared with Results of Noncommercial Codes	GSI, dipole, synchrotron, quadrupole	2595
	P.A. Shcherbakov IHEP Protvino, Protvino, Moscow Region E. Fischer GSI, Darmstadt R.V. Kurnyshov Electroplant, Moscow
	The design of fast ramped superferric magnets with repetition rates in the order of 1Hz requires reliable software tools to calculate the complex 3D magnetic field quality as well as the impact of eddy current and hysteresis loss. Various technological construction details should be taken into account to obtain a high field quality. We present a methodical study of these questions based on ANSYS calculations for simplified dipole models. The details of these analysis are compared with recently published results obtained by different special codes, i.e. an integral and the FIT method. The time dependences of eddy current power due to longitudinal magnetic field component at the yoke ends, the transient field distribution in the yoke volume and the total eddy current loss are investigated, choosing the identical geometry with the same magnetic and electric properties of the lamination steel used by the other codes. The conclusions for the application potential of the different methods are discussed.

WEPLS097	Random Errors in Superconducting Dipoles	LHC, dipole, multipole, RHIC	2601
	B. Bellesia, E. Todesco CERN, Geneva C. Santoni Université Blaise Pascal, Clermont-Ferrand
	The magnetic field in a superconducting magnet is mainly determined by the position of the conductors. Hence, the main contribution to the random field errors comes from random displacement of the coil with respect to its nominal position. Using a Monte-Carlo method, we analyze the measured random field errors of the main dipoles of the LHC, Tevatron, RHIC and HERA projects in order to estimate the precision of the conductor positioning reached during the production. The method can be used to obtain more refined estimates of the random components for future projects.

WEPLS115	Impedances in Slotted-Pipe Kicker Magnets	kicker, impedance, vacuum, storage-ring	2649
	F. Marhauser, O. Dressler, V. Duerr, J. Feikes BESSY GmbH, Berlin
	Storage ring slotted-pipe kicker magnets based on the DELTA design are foreseen for the Metrology Light Source (MLS) of the Physikalisch-Technische Bundesanstalt currently under construction near the BESSY site. Although the slotted pipe maintains the cross-section of the storage ring vacuum chamber, image currents have to bypass the slots generating wakefields. Actually modes with substantial impedances have been revealed by simulations and verified by measurements of a kicker model for the MLS.

WEPLS127	CNAO Storage Ring Dipole Magnet Power Converter 3000A / ±1600V	controls, power-supply, dipole, synchrotron	2673
	M.P.C. Pretelli, F. Burini, S. Carrozza, M. Cavazza, M.F. Farioli, S. Minisgallo, G. Taddia O.C.E.M. S.p.A., Bologna I. De Cesaris CNAO Foundation, Milan M. Incurvati, C. Sanelli INFN/LNF, Frascati (Roma) F. Ronchi, C. Rossi, M. Spera, M. Toniato CASY, Bologna
	This paper will describe the design and simulations of the CNAO Dipole Power Converter rated 3000A / ±1600V. The Power Converter will feed the 16+1 synchrotron bending dipole magnets of the CNAO Storage Ring. The actual design confirms how the choice of a 24-pulses, 4 bridges series-parallel connected, active filter, bipolar voltage, meets the stringent requested technical specification ( 10^-5 of maximum current for the output current residual ripple and setting resolution). The extensive modelling will also be presented. The design includes the strength of the topology design, component de-rating and component standardisation. As the other CNAO power converters, the Storage Ring Dipole Power Converter uses the same digital controller, under licence from the Diamond Light Source.

WEPLS134	Design and Modeling of the Step Down Piezo Transformer	impedance, controls, power-supply, feedback	2691
	C.-Y. Liu, Y.-C. Chien, K.-B. Liu NSRRC, Hsinchu
	The energy conversion and the step down voltage waveform of the piezo transformer are required to achieve optimal working condition of the resonate frequency. To meet this requirement, a reliable and precise instrument is needed to scan the resonated point of the piezo transformer such that the piezo transformer's output performance can meet required specification. In this paper, design and modeling of a new step down piezo transformer deployed in NSRRC is described. This step down piezo transformer is capable of delivering energy conversion with high efficiency performance, which is better than traditional transformer, and the voltage transfer ratio is correct. The simulation circuit model used to develop driver circuit of the piezo transformer is also included in the design of this new step down transformer. It has been tested and proven to be working well in power conversion with excellent efficiency and reliability.

THXFI01	State of the Art in EM Field Computation	gun, dipole, SLAC, TESLA	2763
	C.-K. Ng, V. Akcelik, A.E. Candel, S. Chen, N.T. Folwell, L. Ge, A. Guetz, H. Jiang, A.C. Kabel, K. Ko, L. Lee, Z. Li, E.E. Prudencio, G.L. Schussman, R. Uplenchwar, L. Xiao SLAC, Menlo Park, California
	This presentation will provide an up-to-date survey of the methods and tools for the computation of electromagnetic fields in accelerator systems and components.
	Transparencies

THOAFI01	The Development of Computational Tools for Halo Analysis and Study of Halo Growth in the Spallation Neutron Source Linear Accelerator	quadrupole, linac, emittance, CCL	2768
	D.A. Bartkoski, A.V. Aleksandrov, S.M. Cousineau, S. Henderson, J.A. Holmes ORNL, Oak Ridge, Tennessee
	Computational tools have been developed to quantify the halo in a beam by analyzing beam profiles and identifying the halo particles using the Gaussian area ratio and kurtosis methods. Simulations of various injection quadrupole magnet configurations using three types of initial simulated distributions, along with an analysis of their phase space and rms properties, provides insight into the development of halo in the Spallation Neurton Source linear accelerator. Finally, comparisons with machine beam profile data, taken at the same conditions as that of the simulated data, show how accurately the simulations model the beam and its halo development and provide a better understanding of the best machine configuration with which to minimize beam halo and losses.
	Transparencies

THPCH006	Scaling Laws for the Montague Resonance	emittance, resonance, synchrotron, coupling	2796
	I. Hofmann, G. Franchetti GSI, Darmstadt
	The space-charge-driven Montague resonance is a source of emittance coupling in high-intensity accelerators with un-split tunes. Here we present scaling laws for the stop-band widths, growth rates and crossing behavior of this fourth order resonance. Our results on the coupling can be applied to circular machines as well as to linear accelerators. Based on self-consistent coasting beam simulation we show that for slow crossing of the stop-bands a strong directional dependence exists: in one direction the exchange is smooth and reversible, in the other direction it is discontinuous. We also discuss the combined effect of the Montague resonance and linear coupling by skew quadrupoles.

THPCH011	Wire Compensation of Parasitic Crossings in DAFNE	luminosity, positron, injection, collider	2808
	M. Zobov, D. Alesini, C. Milardi, M.A. Preger, P. Raimondi INFN/LNF, Frascati (Roma) D.N. Shatilov BINP SB RAS, Novosibirsk
	Long-range beam-beam interactions (parasitic crossings) are one of the main luminosity performance limitations for the Frascati e⁺e^- Phi-factory DAFNE. In particular, the parasitic crossings (PC) lead to a substantial lifetime reduction of both beams in collision. This puts a limit on the maximum storable current and, as a consequence, on achievable peak and integrated luminosity. In order to alleviate the problem numerical and experimental studies of the PC compensation with current-carrying wires have been performed at DAFNE. Two such wires have been installed at both ends of the KLOE interaction region. Switching on the wires in accordance with the numerical predictions, improvement in the lifetime of the "weak" beam (positrons) has been obtained at the maximum current of the "strong" one (electrons) without luminosity loss. In this paper we describe the PC effects in DAFNE, summarize the results of numerical simulations on the PC compensation with the wires and discuss the experimental measurements and observations.

THPCH018	Resonance Trapping, Halo Formation and Incoherent Emittance Growth due to Electron Cloud	electron, emittance, resonance, LHC	2820
	E. Benedetto, E. Benedetto Politecnico di Torino, Torino G. Franchetti GSI, Darmstadt G. Rumolo, F. Zimmermann CERN, Geneva
	The pinched electron cloud introduces a tune shift along the bunch, which together with synchrotron motion, leads to a periodic crossing of resonances. The resonances are excited by the longitudinal distribution of the electron cloud around the storage ring. We benchmark the PIC code HEADTAIL against a simplified weak-strong tracking code based on an analytical field model, obtaining an excellent agreement. The simplified code is then used for exploring the long term evolution of the beam emittance, and for studying more realistic lattice models. Results are presented for the CERN SPS and the LHC.

THPCH019	Halo and Tail Generation Studies for Linear Colliders	scattering, CLIC, linac, collimation	2823
	L. Neukermans, H. Burkhardt CERN, Geneva J. Resta-López IFIC, Valencia
	Halo particles in linear colliders can result in significant losses and serious background which may reduce the overall performances. We present a study of various halo generation processes with numerical estimates. The aim is to allow to predict and minimize the halo throughout the accelerator chain including the final focus up to the experimental detectors. We include estimates for the planned CLIC beam line.

THPCH024	An Efficient Formalism for Simulating the Longitudinal Kick from Coherent Synchrotron Radiation	CSR, space-charge, synchrotron, synchrotron-radiation	2829
	D. Sagan Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
	Coherent Synchrotron Radiation (CSR) can severely limit the performance of planned light sources and storage rings which push the envelope to ever higher bunch densities. In order to better simulate CSR, the formalism of Saldin is extended to work at lower energies and shorter length scales. The formalism is also generalized to cover the case of an arbitrary configuration of multiple bends. *E. L. Saldin et al. Nucl. Instrum. Methods Phys. Res., Sect. A 398, 373 (1997).

THPCH025	Electron Cloud Self-consistent Simulations for the SNS Ring	electron, proton, SNS, lattice	2832
	A.P. Shishlo, S.M. Cousineau, V.V. Danilov, S. Henderson, J.A. Holmes, M.A. Plum ORNL, Oak Ridge, Tennessee
	The electron cloud dynamics is simulated for the Spallation Neutron Source ring using the self-consistent electron-cloud model for long-bunched proton beams implemented in the ORBIT code. These simulations feature simultaneous calculations of the dynamics of the proton bunch and of the electron cloud, including electron multipacting using a realistic secondary emission surface model. The frequency spectra and growth rates of the proton bunch transverse instability are studied as functions of the RF cavity voltage. The effectiveness of an electron-cloud instability suppression system is also studied using an ORBIT model of the real feedback system. SNS is a collaboration of six US National Laboratories: Argonne National Laboratory (ANL), Brookhaven National Laboratory (BNL), Thomas Jefferson National Accelerator Facility (TJNAF), Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), and Oak Ridge National Laboratory (ORNL).

THPCH026	Parallel 3-D Space Charge Calculations in the Unified Accelerator Library	space-charge, synchrotron, AGS, instrumentation	2835
	N.L. D'Imperio, A.U. Luccio, N. Malitsky BNL, Upton, Long Island, New York O. Boine-Frankenheim GSI, Darmstadt
	The paper presents the integration of the SIMBAD space charge module in the UAL framework. SIMBAD is a Particle-in-Cell (PIC) code. Its 3-D parallel approach features an optimized load balancing scheme based on a genetic algorithm. The UAL framework enhances the SIMBAD standalone version with the interactive ROOT-based analysis environment and an open catalog of accelerator algorithms. The composite package addresses complex high intensity beam dynamics studies and has been developed as a part of the FAIR SIS 100 project.

THPCH032	Instability Studies Using Evaluated Wake Fields and Comparison with Observations at SOLEIL	impedance, SOLEIL, single-bunch, betatron	2847
	R. Nagaoka SOLEIL, Gif-sur-Yvette
	Beam instability is predicted for SOLEIL using the impedance data obtained through component-wise numerical evaluations. The paper also attempts to make the first comparison with measurements. A key issue for SOLEIL has been to acquire precise knowledge of impedance up to a few tens of GHz, due to short bunches, of chambers which are essentially 3D and additionally NEG coated to a large part, which is expected to enhance the reactive part of the resistive-wall impedance. The predictability of instabilities with the data attained thus becomes a large concern. Wake potentials computed with a 3D code are transformed to impedances and decomposed into a series of resonators, inductive and resistive components, to deduce the wake functions, while for NEG coated chambers, they are numerically Fourier transformed from analytically derived impedances. Both time and frequency domain simulations are performed to predict the longitudinal and transverse instabilities in single bunch, as well as resistive-wall instabilities in multibunch as a function of chromaticity. A multibunch tracking is also performed to investigate the filling pattern dependence of the latter.

THPCH036	Wakefield Calculations for 3D Collimators	SLAC, LEFT, impedance, DESY	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	linac, emittance, TESLA, DESY	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.

THPCH042	Numerical Estimations of Wakefields and Impedances for Diamond Collimators	impedance, DIAMOND, storage-ring, injection	2877
	S.A. Pande, R. Bartolini, R. T. Fielder, M. Jensen Diamond, Oxfordshire
	The storage ring of the Diamond light source will use two collimators, one in horizontal and one in the vertical planes in the injection straight to protect the IDs from the injection and Touschek losses. These collimators, in the form of tapered metallic intrusions in to the vacuum chamber, will generate considerable wake fields and will contribute to the overall machine impedance. In this paper we present the results of ABCI and MAFIA numerical simulations to estimate these effects.

THPCH043	Jitter Studies for the FERMI@ELETTRA Linac	linac, electron, ELETTRA, FEL	2880
	P. Craievich, S. Di Mitri ELETTRA, Basovizza, Trieste A. Zholents LBNL, Berkeley, California
	The FEL project FERMI@ELETTRA* will use the existing linac upgraded to 1.2GeV to produce photon pulses in the wavelength range between 100-10 nm by means of harmonic generation in a seeded scheme. FEL operations foresee stringent requirements for the stability of the global linac output parameters, such as the electron bunch arrival time, peak current, average energy and the slice electron bunch parameters, such as the slice peak current and slice average energy. In order to understand the sensitivity of these parameters to jitters of various error sources along the linac an elaborate study using tracking codes has been performed. As a result, we created a tolerance budget to be used as guidance in the design of the linac upgrade. In this paper we give a detailed description of the applied procedures and present the obtained results. *C. Bocchetta et al. "FERMI@ELETTRA - Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays", this conference.

THPCH044	Beam Break-up Instability in the FERMI@ELETTRA Linac	linac, emittance, BBU, FEL	2883
	S. Di Mitri, P. Craievich ELETTRA, Basovizza, Trieste
	The beam break-up instability is studied for the 1.2 GeV linac of FERMI @ ELETTRA FEL. This instability is driven by transverse wake fields acting on an electron beam travelling off-axis in the accelerating structures due to the launching errors in positions, angles, energy and misalignment of various lattice elements. Two operational scenarios are considered: one with a relatively long electron bunch of 1.5 ps and a moderate peak current of 500 A and one with a shorter bunch of 0.7 ps and a higher peak current of 800 A. Attention is given to the correction of the "banana" shape of the electron bunch caused by the instability. The simulation results are compared with the analytical predictions. C. Bocchetta et al. “FERMI@Elettra – Conceptual Design for a Seeded Harmonic Cascade FEL for EUV and Soft X-rays”, this conference.

THPCH047	Maps for Electron Clouds: Application to LHC	electron, LHC, space-charge, CERN	2889
	T. Demma, S. Petracca U. Sannio, Benevento F. Ruggiero, G. Rumolo, F. Zimmermann CERN, Geneva
	Electron Cloud studies performed so far were based on very heavy computer simulations taking into account photoelectron production, secondary electron emission, electron dynamics, and space charge effects providing a very detailed description of the electron cloud evolution. In a recent paper* it has been shown that, for the typical parameters of RHIC, the bunch-to-bunch evolution of the electron cloud density can be represented by a cubic map. Simulations based on this map formalism are orders of magnitude faster than those based on usual codes. In this communication we show that the map formalism is also reliable in the range of typical LHC parameters, and discuss the dependence of the polynomial map coefficients on the physical parameters affecting the electron cloud (SEY, chamber dimensions, bunch spacing, bunch charge, etc.). *U. Iriso and S. Peggs. "Maps for Electron Clouds", Phys. Rev. ST-AB 8, 024403, 2005.

THPCH049	Simulation Study of Transverse Coupled-bunch Instabilities due to Electron Cloud in KEKB LER	electron, KEKB, quadrupole, positron	2895
	X.W. Dong, S.-I. Kurokawa, K. Ohmi KEK, Ibaraki
	In this paper we report simulation results on the transverse coupled-bunch instabilities (TCBI) due to electron cloud at the KEKB Low Energy Ring (LER). The formation of electron cloud and related TCBI is investigated based on realistic solenoid field model. Studies on electron cloud in Quadrupole which could induce TCBI are also presented in this paper.

THPCH051	The Effect of the Solenoid Field in Quadrupole Magnets on the Electron Cloud Instability in the KEKB LER	electron, quadrupole, KEKB, dipole	2901
	H. Fukuma, J.W. Flanagan, T. Kawamoto, T. Morimoto, K. Oide, M. Tobiyama KEK, Ibaraki F. Zimmermann CERN, Geneva
	The electron cloud instability which causes vertical beam blowup in the KEKB LER is largely suppressed by applying a weak solenoid field to vacuum chambers in the drift region. However the blowup is still observed when the bunch spacing is reduced to 3.27 rf buckets or shorter. A question is where the remaining electron clouds are. To investigate the electron clouds in the quadrupole magnets, solenoids made of flat cables were developed and installed in 88 quadrupole magnets. The field strength of the solenoid is 17 Gauss. The effect of the solenoid field on the blowup is now under beam study. So far no clear effect of the solenoids on the luminosity and the sideband accompanied by the blowup is found. We report on the solenoid system, the results of the experiments and comparison of the experimental results with simulations.

THPCH053	Numerical and Experimental Study of Cooling-stacking Injection in HIMAC Synchrotron	ion, injection, electron, scattering	2907
	E. Syresin JINR, Dubna, Moscow Region K. Noda NIRS, Chiba-shi S. Shibuya AEC, Chiba T. Uesugi KEK, Ibaraki
	The cooling-stacking injection at the HIMAC synchrotron was used to increase the intensity of Ar¹⁸⁺ ion beam. The beam stacking was realized in a horizontal free phase-space, which was created by the HIMAC electron cooler. The stack intensity of (1.5~2.5)·10⁹ ppp was accumulated at an injection intensity of (0.3~1.0)e9. The stack intensity was limitted by the ion lifetime. A peculiarity of present cooling-stacking experiments is related to lifetime difference by a factor of 2~3 of the stack and injected ions. The lifetime of stack ions is determined by vacuum pressure. The new injected ions were slowly lost at multiple scattering on residual gas atoms at diffusion heating in the vertical direction caused by the acceptance of 30pi-mm-mrad and a reduction of cooling force at large betatron amplitudes. The results of numerical simulations and experimental study of cooling-stacking injection on the HIMAC synchrotron are presented.

THPCH057	The Fast Vertical Single-bunch Instability after Injection into the CERN Super Proton Synchrotron	impedance, SPS, emittance, LHC	2913
	E. Métral, G. Arduini, T. Bohl, H. Burkhardt, G. Rumolo CERN, Geneva B. Spataro INFN/LNF, Frascati (Roma)
	Since 2003, high-intensity single-bunch proton beams with low longitudinal emittance have been affected by heavy losses after less than one synchrotron period after injection. The effects of the resonance frequency of the responsible impedance, longitudinal emittance and chromaticity on the intensity threshold were already discussed in detail in 2004, comparing analytical predictions with simulation results. In this paper the evolution of the instability between injection and the time of beam loss is our main concern. Measurements are compared with HEADTAIL simulations. A travelling-wave pattern propagating along the bunch, which is the signature of a Beam Break-Up or Transverse Mode Coupling Instability (TMCI), is clearly identified. The oscillating frequency, near ~1 GHz, is in good agreement with the usual broad-band impedance model deduced from beam-based measurements like the head-tail growth rate vs. chromaticity.

THPCH058	Simulation Study on the Beneficial Effect of Linear Coupling for the Transverse Mode Coupling Instability in the CERN Super Proton Synchrotron	coupling, SPS, impedance, CERN	2916
	E. Métral, G. Rumolo CERN, Geneva
	The intensity threshold of the transverse mode coupling instability in a flat vertical chamber, as in the CERN Super Proton Synchrotron, is much higher in the horizontal plane than in the vertical one. This asymmetry between the transverse planes led us to the idea that linear coupling from skew quadrupoles could be used to increase the intensity threshold. This technique is already applied, for instance, in the CERN Proton Synchrotron, where a slow head-tail horizontal instability due to the resistive-wall impedance is stabilized by linear coupling only, i.e. with neither octupoles nor feedbacks. This paper presents the results of the study of the effect of linear coupling on the transverse mode coupling instability, using the HEADTAIL simulation code.

THPCH060	Simulation Study on the Energy Dependence of the TMCI Threshold in the CERN-SPS	electron, impedance, SPS, space-charge	2922
	G. Rumolo, E. Métral, E.N. Shaposhnikova CERN, Geneva
	This paper concentrates on theoretical studies of Transverse Mode Coupling Instability at the SPS. It shows the expected thresholds based on a HEADTAIL tracking model and on impedance values estimated from previous measurements. First, the effect of space charge is addressed as an important ingredient at the low energies. Subsequently, the change of TMCI threshold possibly induced by a higher injection energy into the SPS (plausible according to the upgrade studies) is investigated and a scaling law with energy is derived.

THPCH064	Comparison of Three CSR Radiation Powers for Particle Bunches and Line Charges	CSR, radiation, synchrotron, synchrotron-radiation	2931
	K.A. Heinemann, G. Bassi, J.A. Ellison UNM, Albuquerque, New Mexico
	We are studying coherent synchrotron radiation (CSR) from arbitrary planar orbits as discussed in another abstract we submitted to EPAC06. It is important to have one-dimensional approximations. Here we report on work constructing and validating such approximations. As part of our work two well known papers by Saldin, Schneidmiller and Yurkov (SSY* are considered which deal with the CSR via a one-dimensional approximation whereby the electron bunch is modelled by a line density. Their one-dimensional approach is important because it is used in various CSR codes and since it serves to some extent as a role model for higher-dimensional models. The present report deals with some general aspects of the work of SSY. In particular, care is taken of the renormalization procedure and of the statistical description in terms of the line density. SSY use a renormalized retarded field whereas the present work uses the radiation field which is defined as half the difference of the retarded and advanced fields. The radiation field came into prominence when Dirac** introduced the Lorentz-Dirac equation. E. L. Saldin, et al. Nucl. Instr. Meth. Phys. Res. A 398, 373 (1997) and 417, 158 (1998).*P.A.M. Dirac, Proc. Roy. Soc. (London) A167, 148 (1938).

THPCH066	Transient Beam Loading in the DIAMOND Storage Ring	DIAMOND, beam-loading, storage-ring, damping	2937
	S. De Santis, J.M. Byrd LBNL, Berkeley, California R. Bartolini Diamond, Oxfordshire
	Harmonic cavity systems have been installed on several 3rd generation light sources to lengthen the bunches and increase the Touschek lifetime. Apart from this beneficial effect, harmonic cavities are known to increase the transient beam loading in high-current machines, due to the presence of gaps in the fill pattern. The amplitude of this effect, which is substantially larger than that caused by the main RF system, can in turn produce considerable variations in bunch length and phase along the train, which result in a significant reduction of the lifetime increase. We have developed a tracking simulation, which we have applied to the analysis of the beam loading transients in Diamond, for the case of passive superconducting harmonic cavities. The influence of beam current, gap amplitude and harmonic cavity tuning on the final lifetime have been studied, as well as the effects of higher-order modes.

THPCH069	BBU Calculations for Beam Stability Experiments on DARHT-2	BBU, impedance, induction, electron	2943
	Y. Tang ATK-MR, Albuquerque, New Mexico K.C.D. Chan, C. Ekdahl LANL, Los Alamos, New Mexico T.P. Hughes Voss Scientific, Albuquerque, New Mexico
	The DARHT-2 (Dual-Axis Radiographic Hydrodynamics Test) facility is expected to produce a 2-kA, 20-MeV, 2-microsecond flattop electron beam pulse. Normal operation requires that the beam exit the accelerator with a normalized transverse emittance of less than 0.15-cm-rad. The beam break up (BBU) instability is a potentially serious effect for a high current linear accelerator. It arises from the interaction between the beam and the cavity modes of the accelerating cells. In support of the beam stability experiments, simulations of BBU for DARHT-2 using the Lamda code have been carried out. The simulations used experimental data for the transverse impedance of the cells. Lamda was benchmarked against results calculated with the LLNL code BREAKUP. For nominal transport parameters, simulation results showed that the BBU growth was not significant in changing the beam spot. For a magnetic field reduced by a factor of 5, BBU growth was over a factor of 100, and the image displacement effect was significant.

THPCH075	Simulation of the Electron Cloud for Various Configurations of a Damping Ring for the ILC	electron, damping, wiggler, positron	2958
	M.T.F. Pivi, T.O. Raubenheimer, L. Wang SLAC, Menlo Park, California K. Ohmi KEK, Ibaraki R. Wanzenberg DESY, Hamburg A. Wolski Liverpool University, Science Faculty, Liverpool F. Zimmermann CERN, Geneva
	In the beam pipe of the Damping Ring (DR) of the International Linear Collider (ILC), an electron cloud may be first produced by photoelectrons and ionization of residual gasses and then increased by the secondary emission process. This paper reports about the work that has been done by the electron cloud assessment international task force group for the recommendation of the ILC Damping Rings baseline design, made in November 2005. We have carefully estimated the secondary electron yield (SEY) threshold for electron cloud build-up and estimated the related single^- and coupled-bunch instabilities that can be caused by the presence of electron cloud as a function of beam current and surface properties, for a variety of optics designs. The result of these studies was an important consideration in the choice of a 6-km design for the ILC damping rings. On the basis of the theoretical and experimental work, the baseline configuration specifies a pair of damping rings for the positron beam to mitigate the effects of the electron cloud.

THPCH090	Stabilization of the ILC Final Focus Using Interferometers	laser, monitoring, quadrupole, target	3000
	D. Urner, P.A. Coe, A. Reichold OXFORDphysics, Oxford, Oxon
	We are developing a system of interferometers that can measure the relative motion between two objects (such as the two final focus quadrupoles) to a few nanometers using interferometric methods. Two instruments are developed at the John Adams Institute at University of Oxford: A distance meter to measure length changes and a straightness monitor to measure perpendicular shifts. We will present technique, results and resolutions of our distance meter prototype. We will also examine their applications at the ILC.

THPCH101	Modeling and Simulation of Longitudinal Dynamics for LER-HER PEP II Rings	feedback, klystron, impedance, controls	3032
	C.H. Rivetta, J.D. Fox, T. Mastorides, D. Teytelman, D. Van Winkle SLAC, Menlo Park, California
	A time domain dynamic model and simulation tool for beam-cavity interactions in LER and HER rings at PEP II is presented. The motivation for this tool is to explore the stability margins and performance limits of PEP II LLRF systems at higher currents and upgraded RF configurations. It also serves as test bed for new control algorithms and to define the ultimate limits of the architecture. The tool captures the dynamical behavior of the beam-cavity interaction based on a reduced model. It includes nonlinear elements in the klystron and signal processing. The beam current is represented by macro-bunches. Multiple RF stations in the ring are represented via one or two single macro-cavities. Each macro-cavity captures the overall behavior of all the 2 or 4 cavity RF stations. This allows modeling the longitudinal impedance control loops interacting with the longitudinal beam model. Validation of simulation tool is in progress by comparing the measured growth rates for both LER and HER rings with simulation results. The simulated behavior of both machines at high currents are presented comparing different control strategies and the effect of non-linear klystrons and the linearizer.

THPCH104	Design and Simulation of the ILC Intra-train Orbit and Luminosity Feedback Systems	feedback, luminosity, kicker, linac	3041
	G.R. White, G.R. White JAI, Oxford D. Schulte CERN, Geneva N.J. Walker DESY, Hamburg
	To maintain luminosity to within a few percent of the design at the International Linear Collider (ILC), beam stability at the IP needs to be maintained at the sub-nanometre level. To achieve the beam stability required in the presence of ground motion, multiple feedback systems are required. The baseline design calls for a 5-Hz system to control the orbit in the Linac and Beam Delivery System (BDS) and an intra-train system to address high-frequency ground motion and mechanical disturbances which cause orbit distortions at the IP between pulses enough to completely destroy the luminosity. Details of the slower feedback systems have been addressed elsewhere. The detailed design and simulation of the intra-train feedback systems are described here. This system controls the vertical position and angle at the IP such that luminosity is maximised. The system brings the beams into collision based on BPM-derived information from the initial bunches of the train. It then tunes the IP collision parameters (both position and angle) based on a fast (bunch-by-bunch) luminosity signal from the BeamCal. The system is implemented in fast digital FPGA logic, designed using Matlab's Simulink. A. Seryi et al. "Issues of Stability and Ground Motion in ILC", Nanobeam 2005.**G. White et al. "Multi-Bunch Simulations of the ILC for Luminosity Performance Studies", PAC2005.

THPCH111	Digital Master Oscillator for the ISIS Synchrotron	controls, synchrotron, lattice, target	3062
	C.W. Appelbee, M.G. Glover CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	Rutherford Appleton Laboratories in Oxfordshire is home to an 800MeV synchrotron particle accelerator called ISIS. Its main function is to direct a beam of protons into a heavy metal target to produce neutrons for scientists to analyse condensed matter. A second harmonic system is being developed to upgrade the beam current from 200uA to 300uA in order to drive a second target station. This is being achieved by the inclusion of four second harmonic cavities to increase the width of the RF bucket. In the past the six fundamental cavities were driven by an analogue master oscillator but the extra cavities will bring more difficultly in the phasing of the system. This could be more easily and precisely controlled by embedding a Direct Digital Synthesis core into an FPGA chip as the heart of a new digital Master Oscillator. This paper describes the initial research and feasibility of such a system for the setting up, phasing and synchronisation of the ten cavities in the ring. It also describes how more of the controls to the oscillator can be encompassed by digital means.

THPCH126	System Development of a Time-of-flight Spectrometer for Surface Analysis of Materials	target, quadrupole, ion, beam-transport	3095
	P. Junphong, Mr. Ano, S. Rattanarin, Dr. Suwannakachorn, T. Vilaithong FNRF, Chiang Mai A. Takahashi Osaka University, Osaka
	To study on design the time-of-flight Rutherford backscattering spectrometry (TOF-RBS) technique for nano-material surface analysis with high resolution. At Fast Neutron Research Facility, FNRF, upgrading of the existing pulsed-beam accelerator from 150-keV of D⁺$ to 280 keV of He⁺ was proposed to use for the most powerful method of a near-surface characterization of materials utilizing TOF-RBS. The beam transport was redesigned based on the multicusp ion source which was designed the extraction and focusing system for optimization by the computer program KOBRA, and the existing beam pulsing system to provide He⁺ ion beam with a few nano-second width and 280-keV acceleration energy. Simulation was done by the computer program Beam Optics, resulting in the beam size at the target position of 1 mm in diameter. The measured beam size was 6 mm in diameter. The optimization of the target position was done by the PARMELA program, to be at 3.14 m from the middle point of the buncher. Components, beam transport characteristics, beam optic simulation, and role of quadrupole magnet were explained. Design and test of the scattering chamber for TOF-RBS were shown and measured by the MCP detector. The quadrupole triplet was designed and constructed at FNRF. Development of TOF-RBS system was implemented in this study. Designing component, fabrication and installation to the accelerator system were completed. Beam extraction and He-scattering tests were done.

THPCH149	Active RF Pulse Compression using Electrically Controlled Semiconductor Switches	coupling, SLAC, plasma, laser	3140
	J. Guo, S.G. Tantawi SLAC, Menlo Park, California
	In this paper, we present the recent results of our research on the ultra-high power fast silicon RF switch and its application on active X-Band RF pulse compression systems. This switch is composed of a group of PIN diodes on a high purity silicon wafer. The wafer is inserted into a cylindrical waveguide operating in the T·10⁰¹ mode. Switching is performed by injecting carriers into the bulk silicon through a high current pulse. Our current design uses a CMOS compatible process and the fabrication is accomplished at SNF (Stanford Nanofabrication Facility). The RF energy is stored in a room-temperature, high-Q 400 ns delay line; it is then extracted out of the line in a short time using the switch. The pulse compression system has achieved a gain of 11, which is the ratio between output and input power. Power handling capability of the switch is estimated at the level of 10MW.

THPCH151	Commissioning of the Laser System for SPARC Photoinjector	laser, cathode, gun, emittance	3146
	C. Vicario, M. Bellaveglia, D. Filippetto, A. Gallo, G. Gatti, A. Ghigo INFN/LNF, Frascati (Roma) P. Musumeci, M. Petrarca INFN-Roma, Roma
	In this paper we report the commissioning of the SPARC photoinjector laser system. In the high brightness photoinjector the quality of the electron beam is directly related to the features of the laser pulse. In fact the temporal pulse shape, the temporization and the transverse distribution of the electron beam is determined by the incoming laser pulse. The SPARC laser system is based on an amplified Ti:Sapphire active medium and the pulse shape is imposed by a programmable acousto-optics dispersive filter. The transfer-line has been designed to reduce the angular jitter and to preserve to the cathode the temporal and spatial features of the laser pulse. The laser system has been integrated with the accelerator apparatus. The diagnostics and the control system has been completed. We present the measured performances and the simulations we carried out.

THPCH152	Temporal Quantum Efficiency of a Micro-structured Cathode	laser, cathode, electron, target	3149
	V. Nassisi, F. Belloni, G. Caretto, D. Doria, A. Lorusso, L. Martina, M.V. Siciliano INFN-Lecce, Lecce
	In this work the experimental and simulation results of photoemission studies for photoelectrons are presented. The cathode used was a Zn disc having the emitting surface morphologically modified. Two different excimer lasers were employed like energy source to apply the photoelectron process: XeCl (308nm, 10ns) and KrF (248nm, 20ns). Experimental parameters were the laser fluence (up to 70 mJ/cm2) and the anode-cathode voltage (up to 20 kV). The output current was detected by a resistive shunt with the same value of the characteristic impedance of the sistem, about 100 ?. In this way, our device was able to record fast current signals. The best values of global quantum efficiency were approximately 5x 10^-6 for XeCl and 1x 10^-4 for KrF laser, while the peaks of the temporal quantum efficiency were 8x 10^-6 and 1.4x10-4, respectively. The higher efficiency for KrF is ascribed to higher photon energy and to Schottky effect. Several electron-beam simulations using OPERA 3-D were carried out to analyze the influence of the geometrical characteristics of the diode. Simulating the photoemission by cathodes with micro-structures the output current was dependent on cathode roughness. L. Martina et al. Rev. Sci. Instrum., 73, 2552 (2002).

THPCH159	Analysis of Microphonic Disturbances and Simulation for Feedback Compensation	feedback, FEL, linac, resonance	3167
	M. Luong, P. Bosland, G. Devanz, E. Jacques CEA, Gif-sur-Yvette
	For FEL projects based on a superconducting linac operating in CW mode, the RF power optimization finally comes up against the microphonics disturbances, which result in an unpredictable detuning of the cavities. A new piezoelectric tuner was developed and mounted on a TTF 9-cell cavity with an appropriate instrumentation. This system enables a full characterization of the disturbances and the tuner behavior. First measurements were made in a horizontal cryomodule at 4.2 K. They set a basis for simulations to assess the possibility of a feedback compensation, which is usually credited as impracticable. The outcome of such a compensation is also shown in terms of acceleration voltage amplitude and phase residual errors.

THPCH160	Theoretical Study and Experimental Result of the RF Coupler Prototypes of Spiral 2	vacuum, coupling, SPIRAL2, pick-up	3170
	Y. Gómez-Martínez, D. Bondoux, JM. Carretta, J.-M. De Conto, M. Fruneau, A. Garrigue, D. Marchand, R. Micoud, E. Vernay, F. Vezzu LPSC, Grenoble P. Balleyguier CEA, Bruyères-le-Châtel M. Di Giacomo GANIL, Caen
	Spiral 2 is a 40 MeV superconducting linac under construction at GANIL. The RF couplers have to provide a 12 kW CW power to the cavities at 88 MHz. Two solutions corresponding to 2 different technologies have been designed and 2 prototypes have been built. We present the technical proposals and issues as well as the results (manufacturing, test at low and high power, multipacting…) leading to the final choice.

THPCH170	Reduction of Dark Current in SPring-8 Linac	electron, linac, gun, synchrotron	3194
	T. Kobayashi, T. Asaka, H. Dewa, H. Hanaki, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken
	In the SPring-8 linac, removal of dark currents generated from an injector part has been studied to enhance the bunch purity of stored beam in the SPring-8 storage ring. We already succeeded in reduction of the dark currents from a thermionic electron gun by a beam deflector of parallel plate electrodes. However, dark currents are also generated in accelerating structures due to the high electric fields. We have been studying removal of the dark currents generated from the first accelerating structure by solenoid coils covering it.

THPCH179	High Power Cavity Combiner for RF Amplifiers	electron, storage-ring, scattering, coupling	3215
	F. Pérez, B. B. Baricevic, D. Einfeld, P. Sanchez ALBA, Bellaterra J.P. Buge, M.L. Langlois, G. Peillex-Delphe TED, Thonon
	A new approach of RF power combination has been developed for the ALBA Storage Ring RF system: a three-port high power Cavity Combiner (CaCo). A prototype has been successfully built and tested in Thales Electron Devices, Thonon, France. The final goal is to combine the power of two 80 kW IOTs at 500 MHz in order to provide a total output power of 160 kW. In this paper, a summary of the analytical and simulation analysis of the expected behaviour is given. In basis of that, the decided geometric constraints and the final design configuration chosen for the prototype production are explained. Low power test results and matching, and finally the high power test performances, are shown. As a conclusion, the RF system of the ALBA Storage Ring will incorporate the CaCo concept to obtain the needed power per cavity from the combination of two IOTs.

THPCH194	Investigation of Using Ferroelectric Materials in High Power Fast RF Phase Shifters for RF Vector Modulation	klystron, insertion, controls, resonance	3248
	J.L. Wilson, Y.W. Kang ORNL, Oak Ridge, Tennessee A.E. Fathy University of Tennessee, Knoxville, Tennessee
	A fast ferroelectric phase shifter controlled by an electric field bias is being investigated for high-power RF phase shifters in vector modulation. Such a device could be used in charged particle accelerators, allowing vector control of the RF power delivered to accelerating RF cavities. Bulk ferroelectric materials, particularly those based on barium-strontium titanate (BST) compounds, have shown promise in high-power applications because of their low loss tangent and high dielectric strength. Such materials have already been investigated for use in fast phase shifters at X-Band frequencies. Several different compositions of BST compounds are investigated in phase shifter prototypes at 402.5 MHz and 805 MHz that could be easily adapted for future large-scale accelerator projects. The ratio of barium versus strontium in the composition is varied from sample to sample. This allows an investigation of the tradeoffs involved between dielectric strength, loss tangent, tunability, and relative permittivity. Since ferroelectrics are by nature nonlinear dielectric compounds, preliminary study on the nonlinear propagation effects is conducted through computer simulation. V. P. Yakovlev et al. Fast X-Band Phase Shifter, Advanced Accelerator Concepts: Eleventh Workshop, 2004.

THPLS023	Wake Computations for the Beam Positioning Monitors of PETRA III	PETRA, electromagnetic-fields, vacuum, insertion	3326
	A.K. Bandyopadhyay, A. Joestingmeier, A.S. Omar Otto-Von-Guericke University, Magdeburg K. Balewski, R. Wanzenberg DESY, Hamburg
	At DESY it is planned to convert the PETRA ring into a synchrotron radiation facility, called PETRA III, in 2007. For proper design of PETRA III it is very important to estimate the wakes due to various discontinuities along the beam pipe. This article is on the wake computations for the beam positioning monitors (BPMs) in the PETRA III beam pipe. Two computer codes, namely MAFIA and Microwave Studio, were used for the electromagnetic field computations. Convergence tests and the agreement between the results of both softwares were taken as criteria in order to validate the results.

THPLS064	Design Concept of the Vacuum System for the 3 GeV Taiwan Photon Source	vacuum, photon, electron, storage-ring	3433
	G.-Y. Hsiung, C.K. Chan, C.-H. Chang, H.P. Hsueh, T.L. Yang NSRRC, Hsinchu J.-R. Chen NTHU, Hsinchu
	The design concept of the vacuum system for the electron storage ring of the Taiwan Photon Source (TPS), 518.4 m in circumference, is described. The vacuum system for the synchrotron light source not only meets the specifications of an electron beam energy of 3 GeV and a beam current at 400 mA but also provides a safety factor of 1.7 (~ 500 mA) at 3.3 GeV at the upper bound. The vacuum system for the storage ring is built with consideration of the following features: (1) Large aluminum bending chambers to simplify the ultra-high vacuum (UHV) structure; (2) Absorbers located as far from the source as possible to reduce the heat load and associated yield of photon stimulated desorption (PSD) as well as the photoelectron; (3) Vacuum pumps located in the antechamber and closed to the absorbers to increase the localized pumping efficiency and to minimize the impedance of beam ducts; (4) Quantity of flanges and bellows is significantly reduced. Configuration of the pumps, results of the simulation for the pressure and thermal stress, and the criteria of the design will be discussed.

THPLS065	Optimization for Taiwan Photon Source Electron Beam Position Monitors through Numerical Simulation	electron, photon, synchrotron, synchrotron-radiation	3436
	H.P. Hsueh, C.-H. Chang, G.-Y. Hsiung, C.-K. Kuan, T.-S. Ueng NSRRC, Hsinchu J.-R. Chen NTHU, Hsinchu
	One of the key steps toward successfully building the newly proposed 3rd generation synchrotron radiation research facility, Taiwan Photon Source (TPS), is to optimize the design of the high resolution electron beam position monitors through numerical simulation. With more advanced electromagnetic simulation tool like MAFIA tailored specifically for particle accelerator, the design for the high resolution electron beam position monitors can be tested in such environment before actually fabricated and physically tested. The design goal of our high resolution electron beam position monitors is to achieve 0.1 micron resolution if allowed by engineering limitations. The design consideration to achieve this 0.1 micron resolution goal will also be discussed. The first design has been carried out and the correlated simulations were also carried out with MAFIA. The results are presented and discussed here. Sensitivity as high as 200 has been achieved at 500 MHz. Further study will also be described.

THPLS074	Ground Vibration Measurement at NSRRC Site	site, storage-ring, background, emittance	3454
	D.-J. Wang, H.-P. Chang, J.-R. Chen, J.P. Wang, J. Wang NSRRC, Hsinchu
	For the future 3GeV TPS project in the NSRRC, ground vibration would be important for this low emittance machine. We have monitored the ground vibration under various experimental conditions at the NSRRC site. Sensors were installed in the bare site, underground 35 meters deep and ground of TLS storage ring, including an electricity shutdown in the NSRRC. From the collected data, we compare the effect about day and night, traffic effect, internal machine vibration propagation. Specific vibration sources and their propagations are also discussed.

THPLS103	Investigations of the Longitudinal Phase Space at PITZ	booster, PITZ, gun, electron	3517
	J.R. Roensch, J. Rossbach Uni HH, Hamburg K. Abrahamyan, G. Asova, J.W. Baehr, G. Dimitrov, H.-J. Grabosch, J.H. Han, O. Kalekin, S. Khodyachykh, S.A. Korepanov, M. Krasilnikov, V. Miltchev, A. Oppelt, B. Petrosyan, S. Riemann, L. Staykov, F. Stephan DESY Zeuthen, Zeuthen D. Lipka, R. Richter BESSY GmbH, Berlin
	The correlation between the positions of the particles in the bunch and their longitudinal momenta has to be analysed in order to optimize photo injectors for Free-Electron Lasers (FELs). Longitudinal phase space measurements at the upgraded PITZ facility* will be presented in this paper. Measurements of the complete longitudinal phase space and its projections behind the gun are compared with simulations. Momentum measurements after a booster cavity will be discussed. *A.Oppelt et al. "Status and first results from the upgraded PITZ facility", FEL Conf. 2005.

THPLS112	Electron Multipacting Observation and Simulation in the APS PAR	electron, vacuum, resonance, beam-loading	3541
	C. Yao, Y.-C. Chae ANL, Argonne, Illinois
	The particle accumulator ring (PAR) has both fundamental and 12th harmonic rf systems. Gap voltage fluctuations were experienced after vacuum work was performed on the PAR during a maintenance period. This has caused intermittent beam instability and prevented us from running the PAR fundamental rf system at normal power level. Our investigation has concluded that the problem was caused by electron multipacting in the center vacuum chamber of the cavity. We were able to suppress the multipacting by applying a solenoid field in the suspected region. Computer simulation is underway in order to find the location and the parameter range of the multipacting. In this paper we report the experimental observations and results of the simulation relevant to the phenomena.

THPLS120	Tracking Simulations and Dynamic Multipole Shimming for Helical Undulators	multipole, undulator, insertion, insertion-device	3562
	G. Wuestefeld, J. Bahrdt, M. Scheer BESSY GmbH, Berlin
	Symplectic and fast tracking simulations of an APPLE type undulator for the BESSY II storage ring are presented. The simulation is based on a multiple harmonic decomposition of the magnetic field and on a generating function approach. Because of the relatively large undulator period length of 112 mm, corrections of the dynamic multipoles are required to achieve a good dynamical aperture.

THPLS125	A Concept on Electric Field Error Compensation for the ANKA Superconductive Undulator	undulator, electron, photon, permanent-magnet	3577
	D. Wollmann, T. Baumbach, A. Bernhard University of Karlsruhe, Karlsruhe S. Casalbuoni, MH. Hagelstein, B.K. Kostka, R. Rossmanith FZK, Karlsruhe G. Gerlach University of Dresden, Institute for Solid-State Electronics, Dresden F. Schoeck, E. Steffens, M. Weisser University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
	In April 2005 a superconductive undulator test device, the so-called SCU14 (period length 14 mm, 100 periods) was installed at ANKA. Before installation, the magnetic field was measured and documented. This was the first test of a superconductive undulator in a storage ring and the dominating questions to be answered were related to the interaction of the undulator with the beam. The field quality was of lower importance and will be improved by a modified mechanical fabrication technique at the next superconductive undulators. Nevertheless, after finishing the fundamental beam tests the question was discussed how one would improve the field quality (minimize the phase error) of the existing undulator by local correction devices. The concepts could be used later in a weaker form for local field corrections at future undulators, if necessary.

THPLS133	Simulations of Electromagnetic Undulator for Far Infrared Coherent Source of TTF at DESY	undulator, electron, radiation, FIR	3595
	E. Syresin, V.V. Borisov, E.A. Matushevsky, N.A. Morozov JINR, Dubna, Moscow Region O. Grimm, M.V. Yurkov DESY, Hamburg J. Rossbach Uni HH, Hamburg
	A perspective extension of the VUV FEL user facility at DESY is infrared coherent source on the base of electromagnetic undulator. The undulator consists of 9 periods, period length is 40 cm long, and peak magnetic field is up to 1.2 T. With the energy of electron beam of 500 MeV maximum radiation wavelength is about 200 mkm. An important feature of the beam formation system of the VUV FEL is the possibility to produce ultra-short, down to 50 mkm rms electron bunches. Such short bunches produce powerful coherent radiation with multi-megawatt power level. FIR coherent source operates in a parasitic mode utilizing electron beam passed VUV undulator. Generation of two-colors by a single electron bunch reveals unique possibility to perform pump-probe experiments with VUV and FIR radiation pulses. In this report we present simulations of the undulator magnetic system and beam dynamics.

THPLS136	Magnetic Field Multipole Measurement with Hall Probe	multipole, undulator, insertion-device, insertion	3604
	Z. Martí LLS, Bellaterra (Cerdanyola del Vallès) J. Campmany ALBA, Bellaterra
	When assembling an insertion device before shimming, sorting algorithms are used to reduce the field errors by choosing the best arrangement of magnetic blocks. In order to carry it out, magnets to be placed in the array are measured with the Helmholtz coil. This yields the magnetic dipolar moment of each one. In fact, Helmholtz coil measurements assume a dipolar filed for each block. The development of narrow gap insertion devices yields a growing interest in the effect of magnetic inhomogeneities. Magnetic inhomogeneities introduce multipolar terms that are added to those corresponding to the multipole development of an ideal magnetic source. However, magnetic inhomogeneities are not measured so far with the Helmholtz coil, because it evaluates the magnetic field far from the magnet, and the multipolar terms decay faster than the dipolar with distance. In order to take into account inhomogeneities, a new approach could be used, based on the measurement of multipoles corresponding to each block. In this paper we propose a method for the fast measurement of the multipoles corresponding to an arbitrary magnetic block, using a Hall probe scanning along a single straight line.